CVE-2026-31657
Description
In the Linux kernel, the following vulnerability has been resolved: batman-adv: hold claim backbone gateways by reference batadv_bla_add_claim() can replace claim->backbone_gw and drop the old gateway's last reference while readers still follow the pointer. The netlink claim dump path dereferences claim->backbone_gw->orig and takes claim->backbone_gw->crc_lock without pinning the underlying backbone gateway. batadv_bla_check_claim() still has the same naked pointer access pattern. Reuse batadv_bla_claim_get_backbone_gw() in both readers so they operate on a stable gateway reference until the read-side work is complete. This keeps the dump and claim-check paths aligned with the lifetime rules introduced for the other BLA claim readers.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
Linux kernel Affected 3 releases
| Version | Status | Fixed in |
|---|---|---|
| 7.0 | Affected | — |
| 3.5 | Affected | — |
| — | Affected | 6.1.169 |
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Fixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 6.12.85-1 |
| sid | Fixed | 6.19.13-1 |
| forky | Fixed | 6.19.13-1 |
| bullseye | Fixed | 6.1.170-1~deb11u1 |
| bookworm | Fixed | 6.1.170-1 |
References
- https://git.kernel.org/stable/c/1f2dc36c297d27733f1b380ea644cf15a361bd7b
- https://git.kernel.org/stable/c/2f55b58b5a0bbed192d60c444a45a49cdf1b545f
- https://git.kernel.org/stable/c/4dee4c0688443aaf5bbec74aa203c851d1d53c35
- https://git.kernel.org/stable/c/7962b522222628596ca9ecc8722efc95367aadbd
- https://git.kernel.org/stable/c/82d8701b2c930d0e96b0dbc9115a218d791cb0d2
- https://git.kernel.org/stable/c/f4858832ddef2f39f21e30b7226bbcd3c4b2bc96
- https://www.suse.com/security/cve/CVE-2026-31657.html
- https://security-tracker.debian.org/tracker/CVE-2026-31657
- https://git.kernel.org/stable/c/5202f071b367ffbc8e279fc7a00db14f5e587f52
- https://git.kernel.org/stable/c/69d1ce9c72eca91203ffdb8d08bacd511100aec6
CWEs
CWE-476
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.