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.

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