CVE-2026-97940

ipv6: fix fib6 walker UAF on seq stop

HIGH
7.8
CVSS Score
Published: September 25, 2026 at 10:22 AM UTC
Updated: October 19, 2026 at 10:17 AM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH7.8
Exploit prediction
EPSS 0.2%

Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: fix fib6 walker UAF on seq stop ipv6_route_iter_active() treats a walker in FWS_U at the table root as already unlinked. fib6_del_route() can move a still-linked walker into that same state when the current leaf is the last route at the root, so ipv6_route_native_seq_stop() skips fib6_walker_unlink(). The seq private object can then be freed while it remains on net->ipv6.fib6_walkers. A later route deletion walks the dangling list and uses the freed walker. Use the list head as membership state and reinitialize it when unlinking. Keep the existing w->node check so a never-started iterator with a zeroed private object is not treated as linked. The same stop helper is used by /proc/net/ipv6_route and by the BPF ipv6_route iterator. The BPF show path only widens the race.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

3.138d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7
Vendor states this is fixed in 05b687ee04f816658f4a9cf586f4d2f129157943 (fixed)
Vendor states this is fixed in 0eede1689610e9eeaf729ba86fd1321799eb91a0 (fixed)
Vendor states this is fixed in 14fdaba201fdff92a3e45994e02bccda409cb19d (fixed)
Vendor states this is fixed in 19b4ed644d68098cc62ab612727f40d30f43476c (fixed)
Vendor states this is fixed in 4553cfafa8d05c4ce20b1d18f79d9bb3b303fc02 (fixed)
Vendor states this is fixed in 63407cddabc5992b5ac03af165559f4a1968a032 (fixed)
Vendor states this is fixed in 9a3f73d62c86271614eda4c43315230896a37018 (fixed)
Vendor states this is fixed in b89b691dd00bf39b9ba39ab9446f8c62f419fa7b (fixed)
Vendor states this is fixed in 3.13 (unaffected)
Vendor states this is fixed in 5.10.271 (unaffected)
Vendor states this is fixed in 5.15.222 (unaffected)
Vendor states this is fixed in 6.1.189 (unaffected)
Vendor states this is fixed in 6.12.111 (unaffected)
Vendor states this is fixed in 6.18.53 (unaffected)
Vendor states this is fixed in 6.6.158 (unaffected)
Vendor states this is fixed in 7.2.7 (unaffected)
Vendor states this is fixed in 7.3 (unaffected)
Vendor states this is fixed in 7.3-rc3 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

CVSS

7.8HIGHLinux
Vector?

Quick Info

StatusRECEIVED

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