CVE-2026-31657: Linux Kernel

Critical severity, CVSS 9.8. EPSS: 0.8% chance of exploitation in the next 30 days.

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.

Affected products

• Linux Linux Kernel: from 3.5.1, before 6.1.169 (fixed in 6.1.169); from 6.2, before 6.6.135 (fixed in 6.6.135); from 6.7, before 6.12.82 (fixed in 6.12.82); from 6.13, before 6.18.23 (fixed in 6.18.23); from 6.19, before 6.19.13 (fixed in 6.19.13); version 3.5 only; …

Published 2026-04-24. Last modified 2026-06-17.