CVE-2024-47685 — netfilter: nf_reject_ipv6: fix nf_reject_ip6_tcphdr_put()
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_reject_ipv6: fix nf_reject_ip6_tcphdr_put() syzbot reported that nf_reject_ip6_tcphdr_put() was possibly sending garbage on the four reserved tcp bits (th->res1) Use skb_put_zero() to clear the whole TCP header, as done in nf_reject_ip_tcphdr_put() BUG: KMSAN: uninit-value in nf_reject_ip6_tcphdr_put+0x688/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:255 nf_reject_ip6_tcphdr_put+0x688/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:255 nf_send_reset6+0xd84/0x15b0 net/ipv6/netfilter/nf_reject_ipv6.c:344 nft_reject_inet_eval+0x3c1/0x880 net/netfilter/nft_reject_inet.c:48 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x438/0x22a0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x41a/0x4f0 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] ipv6_rcv+0x29b/0x390 net/ipv6/ip6_input.c:310 __netif_receive_skb_one_core net/core/dev.c:5661 [inline] __netif_receive_skb+0x1da/0xa00 net/core/dev.c:5775 process_backlog+0x4ad/0xa50 net/core/dev.c:6108 __napi_poll+0xe7/0x980 net/core/dev.c:6772 napi_poll net/core/dev.c:6841 [inline] net_rx_action+0xa5a/0x19b0 net/core/dev.c:6963 handle_softirqs+0x1ce/0x800 kernel/softirq.c:554 __do_softirq+0x14/0x1a kernel/softirq.c:588 do_softirq+0x9a/0x100 kernel/softirq.c:455 __local_bh_enable_ip+0x9f/0xb0 kernel/softirq.c:382 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:908 [inline] __dev_queue_xmit+0x2692/0x5610 net/core/dev.c:4450 dev_queue_xmit include/linux/netdevice.h:3105 [inline] neigh_resolve_output+0x9ca/0xae0 net/core/neighbour.c:1565 neigh_output include/net/neighbour.h:542 [inline] ip6_finish_output2+0x2347/0x2ba0 net/ipv6/ip6_output.c:141 __ip6_finish_output net/ipv6/ip6_output.c:215 [inline] ip6_finish_output+0xbb8/0x14b0 net/ipv6/ip6_output.c:226 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip6_output+0x356/0x620 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:450 [inline] NF_HOOK include/linux/netfilter.h:314 [inline] ip6_xmit+0x1ba6/0x25d0 net/ipv6/ip6_output.c:366 inet6_csk_xmit+0x442/0x530 net/ipv6/inet6_connection_sock.c:135 __tcp_transmit_skb+0x3b07/0x4880 net/ipv4/tcp_output.c:1466 tcp_transmit_skb net/ipv4/tcp_output.c:1484 [inline] tcp_connect+0x35b6/0x7130 net/ipv4/tcp_output.c:4143 tcp_v6_connect+0x1bcc/0x1e40 net/ipv6/tcp_ipv6.c:333 __inet_stream_connect+0x2ef/0x1730 net/ipv4/af_inet.c:679 inet_stream_connect+0x6a/0xd0 net/ipv4/af_inet.c:750 __sys_connect_file net/socket.c:2061 [inline] __sys_connect+0x606/0x690 net/socket.c:2078 __do_sys_connect net/socket.c:2088 [inline] __se_sys_connect net/socket.c:2085 [inline] __x64_sys_connect+0x91/0xe0 net/socket.c:2085 x64_sys_call+0x27a5/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:43 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was stored to memory at: nf_reject_ip6_tcphdr_put+0x60c/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:249 nf_send_reset6+0xd84/0x15b0 net/ipv6/netfilter/nf_reject_ipv6.c:344 nft_reject_inet_eval+0x3c1/0x880 net/netfilter/nft_reject_inet.c:48 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x438/0x22a0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x41a/0x4f0 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] ipv6_rcv+0x29b/0x390 net/ipv6/ip6_input.c:310 __netif_receive_skb_one_core ---truncated---
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 1.4% (30-day exploitation probability)+11
- Technical severity (critical)+10
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Debian Debian Linux, Linux Linux, Linux Linux Kernel).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Debian | Debian Linux | version 11.0 | Vulnerable | NIST National Vulnerability Database |
| Linux | Linux |
≥ c8d7b98bec43faaa6583c3135030be5eb4693acb and < 872eca64c3267dbc5836b715716fc6c03a18eda7version 3.18≥ c8d7b98bec43faaa6583c3135030be5eb4693acb and < 9c778fe48d20ef362047e3376dee56d77f8500d4≥ c8d7b98bec43faaa6583c3135030be5eb4693acb and < 10210658f827ad45061581cbfc05924b723e8922≥ c8d7b98bec43faaa6583c3135030be5eb4693acb and < 7a7b5a27c53b55e91eecf646d1b204e73fa4af93≥ c8d7b98bec43faaa6583c3135030be5eb4693acb and < af4b8a704f26f38310655bad67fd8096293275a2≥ c8d7b98bec43faaa6583c3135030be5eb4693acb and < 7ea2bcfd9bf4c3dbbf22546162226fd1c14d8ad2≥ c8d7b98bec43faaa6583c3135030be5eb4693acb and < fbff87d682e57ddbbe82abf6d0a1a4a36a98afcd and 2 more≥ c8d7b98bec43faaa6583c3135030be5eb4693acb and < dcf48ab3ca2c55b09c8f9c8de0df01c1943bc4e5≥ c8d7b98bec43faaa6583c3135030be5eb4693acb and < 7bcbc4cda777d26c88500d973fad0d497fc8a82e |
Vulnerable | CVE Program (cve.org) e CISA ADP |
| Linux | Linux Kernel | ≥ 6.11 and < 6.11.2≥ 6.7 and < 6.10.13≥ 6.2 and < 6.6.54≥ 5.16 and < 6.1.113≥ 5.11 and < 5.15.168≥ 5.5 and < 5.10.227≥ 4.20 and < 5.4.285≥ 3.18 and < 4.19.323 | Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 9.1 | CVSS 3.1 | Critical | 3.9 | 5.2 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · linux/linux
- SSVC assessment updated
- Record published
- Fix documented
- CVSS changed · 9.1
- Source status changed · → Modified
- Record created in this database
- 2024
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 14, 2026 – Oct 14, 2026
References
13 on the record
- git.kernel.org/stable/c/af4b8a704f26f38310655bad67fd8096293275a2
- git.kernel.org/stable/c/fbff87d682e57ddbbe82abf6d0a1a4a36a98afcd
- git.kernel.org/stable/c/9c778fe48d20ef362047e3376dee56d77f8500d4
- git.kernel.org/stable/c/7bcbc4cda777d26c88500d973fad0d497fc8a82e
- git.kernel.org/stable/c/7a7b5a27c53b55e91eecf646d1b204e73fa4af93
- git.kernel.org/stable/c/dcf48ab3ca2c55b09c8f9c8de0df01c1943bc4e5
- git.kernel.org/stable/c/7ea2bcfd9bf4c3dbbf22546162226fd1c14d8ad2
- git.kernel.org/stable/c/10210658f827ad45061581cbfc05924b723e8922
- git.kernel.org/stable/c/872eca64c3267dbc5836b715716fc6c03a18eda7
- cert-portal.siemens.com/productcert/html/ssa-355557.html
- lists.debian.org/debian-lts-announce/2025/03/msg00002.html
- cert-portal.siemens.com/productcert/html/ssa-265688.html
- lists.debian.org/debian-lts-announce/2025/01/msg00001.html
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 7h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 7h
- Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
- Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
- Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
- Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2024-47685 is "netfilter: nf_reject_ipv6: fix nf_reject_ip6_tcphdr_put()", rated Critical. It affects Debian Linux (Debian); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.1 describes technical severity. EPSS 1.37% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
Comments
Moderated technical discussion. Read the community guidelines.
No comments yet.
Sign in or create an account to comment and suggest corrections.