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Vulnerabilidades publicadas, com severidade, exploração conhecida e fontes oficiais.
CVE-2026-8445
Crítica · 9.8
CWE-79 23/08/2026
Bypass de sanitizador no justhtml via saída Markdown
As versões do justhtml <= 1.11.0 (corrigidas na 1.12.0) não escapam de forma suficiente caracteres significativos para HTML (colchetes angulares) em nós de texto ao converter um documento analisado para Markdown via to_markdown(). Embora um pequeno conjunto de metacaracteres Markdown seja escapado, caracteres como < e > são preservados, de modo que entradas não confiáveis que são seguras em to_html() — incluindo texto com entidades decodificadas (por exemplo <script>) ou texto de elementos analisados como RCDATA/RAWTEXT, como <title>, <textarea>, <noscript> e <plaintext> — podem ser emitidas como HTML bruto na saída Markdown, possibilitando um bypass de sanitizador e potencial cross-site scripting quando essa saída for renderizada.
CVE-2026-7808
Crítica · 9.8
CWE-20 23/08/2026
justhtml before 1.16.0 Multiple Security Issues via Sanitization
justhtml before 1.16.0 contains multiple HTML sanitization bypass issues that can allow active/dangerous content (e.g., script or style) to survive sanitization, potentially leading to cross-site scripting. The issues primarily affect advanced usage rather than the default JustHTML(..., sanitize=True) path for ordinary parsed HTML: mutating or reusing sanitization policy objects (including exported defaults) could weaken later sanitization; programmatic DOM input to sanitize()/sanitize_dom() could miss mixed-case tag names (e.g., ScRiPt, StYlE); crafted programmatic doctype names could serialize into active markup; and custom policies preserving SVG or MathML could allow animation elements, presentation attributes with external url(...) references, or DOM trees mislabeled as namespace="html" to bypass foreign-content checks. Fixed in 1.16.0.
CVE-2026-5388
Crítica · 9.8
CWE-20 23/08/2026
justhtml: falhas de bypass de sanitização HTML (anteriores à 1.15.0)
justhtml anterior à 1.15.0 contém múltiplos problemas de segurança em auxiliares de sanitização de URLs (clean_url_value/clean_url_in_js_string), na serialização HTML, na passagem de Markdown (html_passthrough=True) e em diversos casos de borda de políticas de sanitização personalizadas. Dependendo da configuração, um atacante pode contornar a sanitização para injetar HTML e JavaScript ativos, por exemplo por meio de URLs javascript: codificadas, URLs relativas com barra invertida resolvidas como hosts remotos, nomes programáticos de elementos ou atributos que quebram a marcação, comentários HTML, reintrodução de </textarea> bruto pela passagem de Markdown, ou tags <style>, <meta http-equiv=refresh> e <base href> preservadas em políticas personalizadas. A maioria dos problemas em políticas personalizadas não afeta a configuração padrão sanitize=True; eles afetam principalmente APIs auxiliares, construção programática de DOM, html_passthrough=True e políticas e pipelines de transformação personalizados.
CVE-2026-78155
Crítica · 9.9
CWE-426 23/08/2026
Untrusted Search Path in StackGres
privilege escalation in StackGres operator allows a low-privilege tenant who owns a database to gain administrator privileges
CVE-2026-13598
Crítica · 9.8
CWE-269 23/08/2026
RestrictMate < 1.3.0 - Unauthenticated Privilege Escalation to Administrator
The RestrictMate WordPress plugin before 1.3.0 does not restrict the user role supplied during account registration, allowing unauthenticated attackers to create a new administrator account and gain a logged-in administrator session, leading to full site takeover.
CVE-2026-78050
Crítica · 9.9
CWE-119 22/08/2026
Comfast CF-N1-S Web Management mbox-config sub_41AD7C stack-based overflow
A vulnerability was found in Comfast CF-N1-S 2.6.0.1. The affected element is the function sub_41AD7C of the file /cgi-bin/mbox-config?method=SET§ion=ntp_timezone of the component Web Management. The manipulation of the argument timestr/ntp_client_enabled results in stack-based buffer overflow. It is possible to launch the attack remotely. The exploit has been made public and could be used.
CVE-2026-74730
Crítica · 9.8
22/08/2026
NFS: Pin the 'struct nfs_server' during a FREE_STATEID call
In the Linux kernel, the following vulnerability has been resolved:
NFS: Pin the 'struct nfs_server' during a FREE_STATEID call
Dan Aloni reports that he was able to hit a use-after-free bug if a
FREE_STATEID operation gets delayed for whatever reason. Fix this by
bumping the refcount of the 'struct nfs_server' object for the duration
of the FREE_STATEID so it doesn't get cleaned up from underneath us
while operations are still in flight.
CVE-2026-74727
Crítica · 9.8
22/08/2026
ovpn: skip rehash for peers already removed from by_id
In the Linux kernel, the following vulnerability has been resolved:
ovpn: skip rehash for peers already removed from by_id
ovpn_nl_peer_set_doit() resolves the target peer via
ovpn_peer_get_by_id() before taking ovpn->lock. In the window between
the lookup (which only takes a refcount) and the subsequent
spin_lock_bh(&ovpn->lock), a concurrent OVPN_CMD_PEER_DEL, keepalive
expiry, or socket teardown can take ovpn->lock first, run
ovpn_peer_remove() to unhash the peer from all four tables (by_id,
by_vpn_addr4/6, by_transp_addr) and release the lock. set_doit then
acquires ovpn->lock and calls ovpn_peer_hash_vpn_ip(), which
re-inserts the now-removed peer back into the rehashing tables.
The same race affects the float path: ovpn_peer_endpoints_update()
holds only a refcount and acquires ovpn->lock very late (after async
AEAD decrypt and a netlink notification), then rehashes the peer
in the by_transp_addr table.
The resurrected peer becomes reachable again from the RX lookup
(ovpn_peer_get_by_transp_addr) and the TX VPN-IP lookup, even though
userspace believes it is gone. Once the data-path refcount drops the
peer is freed via call_rcu while the hash entries embedded in it
remain linked, opening a UAF window.
Bail out of the rehash when hash_entry_id is unhashed, mirroring
the sentinel already used by ovpn_peer_remove() to detect the
already-removed state. The check is safe under ovpn->lock, which
serializes every mutation of hash_entry_id, and is a no-op for the
add path because ovpn_peer_add_mp() inserts hash_entry_id before
calling ovpn_peer_hash_vpn_ip().
CVE-2026-74723
Crítica · 9.8
22/08/2026
btrfs: lzo: reject inline extents without valid headers
In the Linux kernel, the following vulnerability has been resolved:
btrfs: lzo: reject inline extents without valid headers
[BUG]
For a crafted btrfs image, the following KASAN can be triggered when
reading an inline lzo compressed file extent:
BUG: KASAN: slab-out-of-bounds in lzo_decompress+0x57d/0x700
Read of size 4 at addr ffff888006f2e644 by task btrfs_lzo_inlin/77
Call Trace:
<TASK>
dump_stack_lvl+0x5b/0x70
print_report+0xd1/0x610
kasan_report+0xe0/0x110
__asan_report_load_n_noabort+0x13/0x20
lzo_decompress+0x57d/0x700
btrfs_decompress+0x140/0x1c0
uncompress_inline+0x147/0x1b0
btrfs_get_extent+0xb23/0x10a0
btrfs_do_readpage.constprop.0+0x538/0x1ac0
btrfs_readahead+0x32f/0x5f0
read_pages+0x16f/0x850
page_cache_ra_unbounded+0x296/0x490
do_page_cache_ra+0xd9/0x130
page_cache_sync_ra+0x3ee/0x6f0
filemap_get_pages+0x306/0x15c0
filemap_read+0x329/0xd00
btrfs_file_read_iter+0x1f8/0x2b0
vfs_read+0x4ef/0x720
ksys_read+0xf8/0x1d0
__x64_sys_read+0x71/0xb0
x64_sys_call+0x1ab0/0x1b70
do_syscall_64+0x61/0x470
entry_SYSCALL_64_after_hwframe+0x4b/0x53
</TASK>
[CAUSE]
For an inline lzo compressed file extent, there should always be one lzo
header, recording the total length of the compressed data, followed by
one segment header, recording the compressed lzo payload.
But if a crafted inline lzo compressed file extent contains only an lzo
header, without the segment header or payload, lzo_decompress() will
still try to read the segment header, causing a read beyond the item
boundary.
Furthermore if the inline lzo compressed file extent is the first item
of the leaf, it will be at the extent buffer boundary. The above
out-of-boundary read will go beyond the extent buffer boundary,
triggering the above KASAN report.
[FIX]
Validate the total length of the inlined lzo compressed file extent, to
make sure there is at least one LZO header and one segment header, and a
non-zero payload.
[ Rework the commit message to remove slop ]
CVE-2026-74712
Crítica · 9.3
22/08/2026
vdpa/mlx5: Fix buffer length in create_direct_keys()
In the Linux kernel, the following vulnerability has been resolved:
vdpa/mlx5: Fix buffer length in create_direct_keys()
We have seen in our CI the following KASAN message:
BUG: KASAN: slab-out-of-bounds in cmd_exec+0x550/0xca0 [mlx5_core]
Read of size 272 at addr 0000000176795020 by task qemu-system-s39/82764
[...]
[<000011388ab3a7a0>] cmd_exec+0x550/0xca0 [mlx5_core]
[<000011388ab3b61c>] mlx5_cmd_exec_cb+0x25c/0x4f0 [mlx5_core]
[<000011388b21e82e>] mlx5_vdpa_exec_async_cmds+0x22e/0x5e0 [mlx5_vdpa]
[<000011388b21fd44>] create_direct_keys+0x954/0xef0 [mlx5_vdpa]
[...]
The buggy address is located 4128 bytes inside of
allocated 4384-byte region [0000000176794000, 0000000176795120)
So in essence we read 16 bytes beyond 4384-byte allocation.
create_direct_keys calculates the pointer and length for in and out
buffers.
The size calculation for in includes the entire structure
size (out + in + mtt[]) but the pointer passed to cmd_exec points only
to the 'in' field, skipping the 'out' field.
This causes mlx5_copy_to_msg() to read beyond the allocated buffer
by sizeof(out) bytes when copying command data.
Properly calculate the input size to match the pointer and allocation size.
CVE-2026-74705
Crítica · 10.0
22/08/2026
udp: fix potential use-after-free in tunnel segmentation
In the Linux kernel, the following vulnerability has been resolved:
udp: fix potential use-after-free in tunnel segmentation
__skb_udp_tunnel_segment() gets the UDP header before ensuring the
tunnel header is in the skb head. If the pull reallocates skb->head,
the saved UDP header pointer is no longer valid.
Get the UDP header after the pull to avoid a potential use-after-free.
CVE-2026-74688
Crítica · 9.8
22/08/2026
sctp: clear control chunk transport if it is being removed
In the Linux kernel, the following vulnerability has been resolved:
sctp: clear control chunk transport if it is being removed
sctp_make_heartbeat_ack() caches the destination transport in
chunk->transport without taking a reference. When src_out_of_asoc_ok is
enabled, the HEARTBEAT ACK may remain queued on control_chunk_list instead
of being transmitted immediately.
If the peer transport is removed while the chunk is still queued,
sctp_assoc_rm_peer() drops the transport and schedules it for RCU freeing,
but only clears cached transport pointers in out_chunk_list. The queued
control chunk therefore retains a dangling transport pointer.
Once an ASCONF_ACK clears the suppression and the queued control chunk is
transmitted, SCTP dereferences the stale transport pointer, leading to a
use-after-free.
Fix this by also clearing chunk->transport for queued control chunks in
control_chunk_list when removing the transport.
CVE-2026-74669
Crítica · 9.8
22/08/2026
ipvs: clear IPv4 options after rebasing tunnel ICMP errors
In the Linux kernel, the following vulnerability has been resolved:
ipvs: clear IPv4 options after rebasing tunnel ICMP errors
ip_vs_in_icmp() rebases an skb from the outer ICMP packet to the
quoted original request before passing it to icmp_send(). However,
IPCB(skb)->opt still describes the outer IPv4 header.
A timestamp option in the outer header can therefore leave an offset
that points into the quoted transport header after the rebase.
__ip_options_echo() treats a byte at that stale location as the option
length and copies it into the fixed-size option storage on the
__icmp_send() stack, causing a stack out-of-bounds write.
Clear the stale option metadata after resetting the network header.
Keep the remaining control block fields, including the ingress
interface used by the ICMP response path.
CVE-2026-74665
Crítica · 9.1
22/08/2026
net: fix skb length accounting after generic XDP frag adjustment
In the Linux kernel, the following vulnerability has been resolved:
net: fix skb length accounting after generic XDP frag adjustment
Generic XDP exposes non-linear skb fragments through an xdp_buff. If an
XDP program adjusts the fragment area, bpf_prog_run_generic_xdp() copies
xdp_frags_size back to skb->data_len but leaves skb->len containing the
old fragment contribution.
After a fragment shrink, this makes skb_headlen() larger than the actual
linear area. In the reproduced UDP receive path, __skb_datagram_iter()
copied 1024 bytes past the actual linear tail to userspace, starting at
struct skb_shared_info. The copied bytes included the affected skb's
nr_frags, xdp_frags_size and a kernel pointer from
skb_shinfo(skb)->frags[0]. Real packet data was displaced by the same
amount and truncated at the end.
Subtract the old data_len before replacing it and add the new data_len
afterwards, keeping skb->len and skb->data_len synchronized.
A 60000-byte UDP datagram on a veth pair with MTU 64000 was shortened by
1024 bytes from its fragment area. Before the fix, all 10 runs produced
corrupted payloads. After the fix, all 10 runs matched the expected
payload exactly.
CVE-2026-74662
Crítica · 9.8
22/08/2026
inet: frags: publish queues before arming timer
In the Linux kernel, the following vulnerability has been resolved:
inet: frags: publish queues before arming timer
inet_frag_create() arms the fragment queue timer before inserting the
queue into the fqdir rhashtable. If the namespace fragment timeout is
zero or negative, the timer can run before the queue is published.
The timer callback then marks the queue complete, tries to remove a node
that is not in the hash table yet, and drops the anticipated hash
reference. Creation can subsequently publish the completed queue without
restoring that reference, leaving a stale hash node after the caller drops
the remaining reference.
Publish the queue first and arm the timer while holding the queue lock.
This makes timer expiry wait until the queue is visible in the hash table,
so inet_frag_kill() can remove the node and balance the hash reference.
CVE-2026-74628
Crítica · 9.8
22/08/2026
net/x25: fix use-after-free of the socket by its timers
In the Linux kernel, the following vulnerability has been resolved:
net/x25: fix use-after-free of the socket by its timers
The x25 timers are armed with mod_timer() and cancelled with
timer_delete(), so a pending timer holds no reference on the socket and a
cancel does not wait for a callback already running on another CPU.
x25_heartbeat_expiry() also rearms unconditionally, so it can reinstall
sk->sk_timer after __x25_destroy_socket() has passed its cancel point.
The following __sock_put() frees the socket while the timer is still
queued, and the next expiry uses freed memory. KASAN reports a
slab-use-after-free on the kmalloc-2k object freed by close().
timer_delete_sync() cannot be used here: x25_heartbeat_expiry() and
x25_timer_expiry() both reach the cancels from inside the timer they
would wait on, through __x25_destroy_socket() and x25_disconnect().
Arm the timers with sk_reset_timer() and cancel them with sk_stop_timer()
so that an armed timer owns a reference, and release it in both expiry
handlers. Rearm the heartbeat only while sk_hashed(sk) is still true,
since __x25_destroy_socket() unlinks the socket before dropping it. Arm
the deferred destroy timer the same way and drop its reference in
x25_destroy_timer().
Reproduced on net with KASAN, with the heartbeat period shortened so the
window recurs. With this patch the reproducer no longer triggers a
report and /proc/net/x25 drains.
Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>
CVE-2026-74617
Crítica · 9.8
22/08/2026
dibs: initialise dibs->lock in dibs_dev_alloc()
In the Linux kernel, the following vulnerability has been resolved:
dibs: initialise dibs->lock in dibs_dev_alloc()
dibs->lock is initialised by dibs_dev_add(), but a dibs device can
already take interrupts before that call: ism_probe() runs
ism_dev_init(), and hence request_irq(), before it calls
dibs_dev_add(). No client can have registered a dmb at that point, so
no dmb interrupt can occur, but a GID event interrupt can, and
ism_handle_irq() takes dibs->lock unconditionally on entry, before it
inspects anything else.
Initialise the lock in dibs_dev_alloc() instead, so that it is valid as
soon as a driver can publish the device to its interrupt handler.
CVE-2026-74616
Crítica · 9.8
22/08/2026
xdp: reject clones that overrun skb_shared_info tailroom
In the Linux kernel, the following vulnerability has been resolved:
xdp: reject clones that overrun skb_shared_info tailroom
xdpf_clone() clones broadcast copies into a single page and sets
frame_sz to PAGE_SIZE. __xdp_build_skb_from_frame() later treats that
page like a normal XDP frame and expects the usual skb_shared_info
tailroom at the end of the buffer.
The current check only rejects frames whose linear xdp_frame header,
headroom, and packet data exceed PAGE_SIZE. A source frame backed by a
larger allocation can still satisfy that check while extending into the
clone's required shared-info area. When such a clone is converted back
into an skb, build_skb_around() places skb_shared_info over live packet
bytes and later writes can corrupt XDP return metadata.
Reject clones unless their linear area fits inside
SKB_WITH_OVERHEAD(PAGE_SIZE), matching the tailroom requirement already
enforced by the XDP-to-skb conversion path.
CVE-2026-74612
Crítica · 10.0
22/08/2026
veth: fix skb length accounting after XDP frag adjustment
In the Linux kernel, the following vulnerability has been resolved:
veth: fix skb length accounting after XDP frag adjustment
veth exposes non-linear skb fragments through an xdp_buff. If an XDP
program adjusts the fragment area, veth_xdp_rcv_skb() copies
xdp_frags_size back to skb->data_len but leaves skb->len containing the
old fragment contribution.
After a fragment shrink, this makes skb_headlen() larger than the actual
linear area. In the reproduced UDP receive path, __skb_datagram_iter()
copied 1024 bytes past the actual linear tail to userspace, starting at
struct skb_shared_info. The copied bytes included the affected skb's
nr_frags, xdp_frags_size, and a kernel pointer from
skb_shinfo(skb)->frags[0]. Real packet data was displaced by the same
amount and truncated at the end.
Subtract the old data_len before replacing it and add the new data_len
afterwards, keeping skb->len and skb->data_len synchronized.
Additionally, bpf_xdp_pull_data() can advance data_end while leaving
frags present. The skb is then still non-linear, so the old
__skb_put(skb, off) triggers SKB_LINEAR_ASSERT().
Use skb_set_tail_pointer() and update skb->len explicitly instead,
following bpf_prog_run_generic_xdp(). Unlike __skb_put(),
skb_set_tail_pointer() does not require a linear skb.
A 60000-byte UDP datagram on a veth pair with MTU 64000 was shortened by
1024 bytes from its fragment area. Before the fix, all 10 runs produced
corrupted payloads. After the fix, all 10 runs matched the expected
payload exactly. A forced-tailroom reproducer also exercises
bpf_xdp_pull_data() with frags still present; the old code triggers
SKB_LINEAR_ASSERT(), while this fix passes 10/10 runs.
CVE-2026-74611
Crítica · 9.8
22/08/2026
tls: rx: restore msg_iter before TLS 1.3 optimistic retry
In the Linux kernel, the following vulnerability has been resolved:
tls: rx: restore msg_iter before TLS 1.3 optimistic retry
tls_decrypt_sg() advances msg->msg_iter when it maps user pages for
the optimistic TLS 1.3 zero-copy path. If the decrypted record turns
out not to be unpadded application data, tls_decrypt_sw() retries into
a kernel skb, but leaves the iterator advanced.
The subsequent copy from the skb then writes decrypted bytes again at
a later point in the caller iovecs while recvmsg() reports only the
post-retry length. A TLS peer can trigger this after the receiver
enables TLS_RX_EXPECT_NO_PAD.
Revert the iterator by the number of bytes consumed by the optimistic
mapping before retrying without zero-copy.
Add a selftest which sends a TLS 1.3 control record with
TLS_RX_EXPECT_NO_PAD enabled and verifies that recvmsg() does not
overwrite later iovecs beyond the returned length.
CVE-2026-74608
Crítica · 9.8
22/08/2026
smb: client: Fix use-after-free in cifs_try_adding_channels()
In the Linux kernel, the following vulnerability has been resolved:
smb: client: Fix use-after-free in cifs_try_adding_channels()
cifs_try_adding_channels() takes a temporary reference to an interface
before dropping iface_lock. If cifs_ses_add_channel() fails, it drops
that reference and then increments iface->weight_fulfilled.
A concurrent interface list refresh can remove the list reference while
channel creation is in progress. In that case, the failure-path
kref_put() releases the last reference and frees iface. Updating
weight_fulfilled afterward then accesses freed memory.
Increment weight_fulfilled before dropping the temporary reference,
keeping iface alive for the final access.
CVE-2026-74597
Crítica · 9.8
22/08/2026
ip6_tunnel: clear skb2->cb[] in ip6ip6_err()
In the Linux kernel, the following vulnerability has been resolved:
ip6_tunnel: clear skb2->cb[] in ip6ip6_err()
ip6ip6_err() clones an outer IPv6 ICMP error skb, pulls it to the
quoted inner IPv6 packet, and then passes the clone to icmpv6_send().
The clone still carries the outer packet's inet6_skb_parm in skb->cb.
If the outer packet had a Home Address Option, IP6CB(skb2)->dsthao
remains non-zero after skb_pull(). icmpv6_send() later calls
mip6_addr_swap(), which uses that stale dsthao offset against the quoted
inner packet. A malformed inner destination-options header can then make
the HAO lookup and address swap run past the end of the quoted packet
and corrupt skb_shared_info.
Clear skb2->cb[] before pulling the quoted inner IPv6 packet so the
reply path does not reuse metadata left by the outer IPv6 stack.
CVE-2026-74591
Crítica · 9.8
22/08/2026
mm/filemap: __filemap_add_folio() restore index before retrying
In the Linux kernel, the following vulnerability has been resolved:
mm/filemap: __filemap_add_folio() restore index before retrying
In __filemap_add_folio()'s split-a-conflict loop, xas_set_order() is
applied repeatedly: each application modifies xas.xa_index, rounding it
down according to the split_order attempted at that stage: and if all goes
as intended, it eventually (or immediately) converges on an
xas_try_split() to the required folio_order, with xas.xa_index now the
same as index: then xas_store() puts the new folio into the xarray there.
But if a new node was needed, and GFP_NOWAIT allocation did not get one,
the lock is dropped, xas_nomem() used to allocate, and sequence retried.
If (that part of) the xarray is unchanged when the lock is reacquired, no
problem. But what if the conflict was meanwhile resolved by another
thread (perhaps even doing the same thing, inserting a folio at that same
index)? Isn't there a danger of now putting our folio into the xarray at
an intermediate rounded-down index? With !folio_contains() bug to follow,
when CONFIG_DEBUG_VM=y is checking for that.
Fix this with an xas_set_order() to restore the original xas.xa_index at
the bottom of the loop, so the retry does a full re-evaluation after
reacquiring the lock, and cannot reach xas_store() with the wrong index.
Production was suffering from rare SIGILLs and SIGSEGVs, executable text
found a page away from where it belonged, !folio_contains() bug hit when
debug enabled: symptoms not seen since this patch went in.
CVE-2026-74588
Crítica · 9.8
22/08/2026
sctp: keep chunk->transport in step with the list it is queued on
In the Linux kernel, the following vulnerability has been resolved:
sctp: keep chunk->transport in step with the list it is queued on
__sctp_outq_flush_rtx() moves a gap-acked chunk onto another transport's
transmitted list without updating chunk->transport:
if (chunk->tsn_gap_acked) {
list_move_tail(&chunk->transmitted_list,
&transport->transmitted);
continue;
}
The chunk then sits on a live transport's list while chunk->transport still
names a different one. If that transport is removed - sctp_assoc_rm_peer()
from an ASCONF Delete-IP - sctp_transport_free() RCU-frees it and the chunk
is left with a dangling pointer. sctp_assoc_rm_peer() scrubs
peer->transmitted and asoc->outqueue.out_chunk_list, but the chunk is on
neither.
The pointer is not followed while tsn_gap_acked is set. A SACK that
reneges on the TSN clears the flag, and the next SACK reaches
tchunk->transport->flight_size -= sctp_data_size(tchunk);
inside the freed transport. KASAN reports a slab-use-after-free read in
sctp_check_transmitted(), freed from sctp_assoc_rm_peer(). Both the
removal and the SACKs come from the association peer.
Set chunk->transport at the move. The ordinary resend path needs nothing:
it reaches its list_move_tail() only after sctp_packet_append_chunk()
returned SCTP_XMIT_OK, and __sctp_packet_append_chunk() has rebound the
chunk by then.
Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>
CVE-2026-74587
Crítica · 9.8
22/08/2026
sctp: fix use-after-free of cached ASCONF chunk
In the Linux kernel, the following vulnerability has been resolved:
sctp: fix use-after-free of cached ASCONF chunk
addip_last_asconf caches the outstanding outbound ASCONF chunk. The normal
ASCONF-ACK completion path releases the chunk and clears the pointer.
However, sctp_asconf_queue_teardown() releases the cached chunk without
clearing addip_last_asconf. During peer restart handling,
sctp_sf_do_dupcook_a() queues SCTP_CMD_PURGE_ASCONF_QUEUE, which invokes
sctp_asconf_queue_teardown() while the association remains alive and leaves
the pointer dangling.
A delayed authenticated ASCONF-ACK can then reach sctp_sf_do_asconf_ack(),
which accesses the stale chunk and passes it to sctp_process_asconf_ack(),
causing a use-after-free and a second release.
Clearing the pointer exposes a race with T4 expiry. Peer restart handling
queues the timer stop before the purge, but SCTP_CMD_TIMER_STOP uses
timer_delete(), which does not wait for a callback already running on
another CPU. Such a callback can reach sctp_sf_t4_timer_expire() after
the purge and dereference NULL.
Clear addip_last_asconf after releasing the cached chunk, and make
sctp_sf_t4_timer_expire() consume a stale T4 expiry if no outstanding
ASCONF remains.