ipv6: fix fib6 walker UAF on seq stop
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 7 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2.7, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-97940
- 2026-10-03 Alias added: GHSA-g66h-hcwj-f29f
- 2026-10-03 Fix available: Linux/Linux@05b687ee04f816658f4a9cf586f4d2f129157943, Linux/Linux@14fdaba201fdff92a3e45994e02bccda409cb19d, Linux/[email protected] +5 · CNA
- 2026-10-03 4 new references · CNA
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-30 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/9a3f73d62c86271614eda4c43315230896a37018
- https://git.kernel.org/stable/c/63407cddabc5992b5ac03af165559f4a1968a032
- https://git.kernel.org/stable/c/05b687ee04f816658f4a9cf586f4d2f129157943
- https://git.kernel.org/stable/c/14fdaba201fdff92a3e45994e02bccda409cb19d
- https://git.kernel.org/stable/c/0eede1689610e9eeaf729ba86fd1321799eb91a0
- https://git.kernel.org/stable/c/b89b691dd00bf39b9ba39ab9446f8c62f419fa7b
- https://git.kernel.org/stable/c/4553cfafa8d05c4ce20b1d18f79d9bb3b303fc02
- https://git.kernel.org/stable/c/19b4ed644d68098cc62ab612727f40d30f43476c
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Sources
- CVE-2026-97940 · CVE Program
- CVE-2026-97940 · NVD
- FIRST EPSS
- GHSA-g66h-hcwj-f29f · GitHub Advisory Database · CC BY 4.0
- CVE-2026-97940 · Red Hat security data · CC BY 4.0
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