Unknown

CVE-2026-64572 — ipv4: fib: free fib_alias with kfree_rcu() on insert error path

In the Linux kernel, the following vulnerability has been resolved: ipv4: fib: free fib_alias with kfree_rcu() on insert error path fib_table_insert() publishes new_fa into the leaf's fa_list with fib_insert_alias() before calling the fib entry notifiers. When a notifier fails, the error path removes new_fa with fib_remove_alias() (hlist_del_rcu) and frees it right away with kmem_cache_free(). fib_table_lookup() walks that list under rcu_read_lock() only, so a concurrent lookup that already reached new_fa keeps reading it after the free: BUG: KASAN: slab-use-after-free in fib_table_lookup (net/ipv4/fib_trie.c:1601) Read of size 1 at addr ffff88810676d4eb by task exploit/297 Call Trace: fib_table_lookup (net/ipv4/fib_trie.c:1601) ip_route_output_key_hash_rcu (net/ipv4/route.c:2814) ip_route_output_key_hash (net/ipv4/route.c:2705) __ip4_datagram_connect (net/ipv4/datagram.c:49) udp_connect (net/ipv4/udp.c:2144) __sys_connect (net/socket.c:2167) __x64_sys_connect (net/socket.c:2173) do_syscall_64 entry_SYSCALL_64_after_hwframe which belongs to the cache ip_fib_alias of size 56 Triggering the error path needs CAP_NET_ADMIN and a registered fib notifier that can reject a route; a netdevsim device whose IPv4 FIB resource is exhausted is enough. Free new_fa with alias_free_mem_rcu(), as fib_table_delete() already does for a fib_alias removed from the trie.

Published Aug 5, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.2% (30-day exploitation probability)+2

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.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.2%

ahead of 10% of scored CVEs · Oct 30, 2026

Affects

Linux

CVSS base

—

Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

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 (Linux Linux).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ a6c76c17df021b141b0d306828c9fe4ba2d2717c and < 9d0778571def598c31e84a38ae5a7ebc6f65e6d8≥ a6c76c17df021b141b0d306828c9fe4ba2d2717c and < bb03350f974aec352b660d032a1d283eb462165a≥ a6c76c17df021b141b0d306828c9fe4ba2d2717c and < 6429c9cfd941e62acd7bb0bc64d631574d4c3b2a≥ a6c76c17df021b141b0d306828c9fe4ba2d2717c and < 8150b5365f026e72250cacc527ea00be30f40105≥ a6c76c17df021b141b0d306828c9fe4ba2d2717c and < d007056868723de9c0cc3f5ffaad47a8d468b9a4≥ a6c76c17df021b141b0d306828c9fe4ba2d2717c and < cb8be318b4432abd88d3172ec157330f27a5f7a7≥ a6c76c17df021b141b0d306828c9fe4ba2d2717c and < b8d2ea75c76abcd0d72679c2f488271f573e32fb≥ a6c76c17df021b141b0d306828c9fe4ba2d2717c and < f2f152e94a67bc746afaf05a1b2702c195553112 and 1 more version 5.6	Vulnerable	CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 15, 2026 → Oct 30, 2026 · 15 reading(s) · max 0.20%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Not enough vector or weakness data: use the affected application’s logs as a starting point.

application logs

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 15, 2026
Affected products added · linux/linux
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Source status changed · → Received
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Aug 5, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

8 on the record

git.kernel.org/stable/c/9d0778571def598c31e84a38ae5a7ebc6f65e6d8
NIST National Vulnerability Database
git.kernel.org/stable/c/d007056868723de9c0cc3f5ffaad47a8d468b9a4
NIST National Vulnerability Database
git.kernel.org/stable/c/b8d2ea75c76abcd0d72679c2f488271f573e32fb
NIST National Vulnerability Database
git.kernel.org/stable/c/8150b5365f026e72250cacc527ea00be30f40105
NIST National Vulnerability Database
git.kernel.org/stable/c/cb8be318b4432abd88d3172ec157330f27a5f7a7
NIST National Vulnerability Database
git.kernel.org/stable/c/f2f152e94a67bc746afaf05a1b2702c195553112
NIST National Vulnerability Database
git.kernel.org/stable/c/bb03350f974aec352b660d032a1d283eb462165a
NIST National Vulnerability Database
git.kernel.org/stable/c/6429c9cfd941e62acd7bb0bc64d631574d4c3b2a
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

High CVE-2026-99216 Drivers: hv: Don't reset VMBus connection state on error/exit paths 3d
Unknown CVE-2026-99215 power: supply: core: prevent unregistering a power supply while a callback runs 3d
Unknown CVE-2026-99207 scsi: target: Disable interrupts while holding delayed_cmd_lock 3d
Unknown CVE-2026-99208 drm/xe/oa: Zero OA buffer at allocation 3d
Unknown CVE-2026-99209 drm/xe: skip eviction of a BO with no resource 3d
Unknown CVE-2026-99210 accel/rocket: clear rdev on device init failure 3d

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 CVSS score published by NVD, the CNA, CISA or GitHub so far.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
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-2026-64572 is "ipv4: fib: free fib_alias with kfree_rcu() on insert error path", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.20% 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.

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