Paper/Archive/CVE-2026-31657

CVE-2026-31657

Linux Linux — batman-adv: hold claim backbone gateways by reference

Description · from the CVE record

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

ProductAffectedFixed inSource
Linux23721387c409087fd3b97e274f34d3ddc0970b74 – < 5202f071b367ffbc8e279fc7a00db14f5e587f525202f071b367ffbc8e279fc7a00db14f5e587f52CNA
Linux23721387c409087fd3b97e274f34d3ddc0970b74 – < 69d1ce9c72eca91203ffdb8d08bacd511100aec669d1ce9c72eca91203ffdb8d08bacd511100aec6CNA
Linux23721387c409087fd3b97e274f34d3ddc0970b74 – < f4858832ddef2f39f21e30b7226bbcd3c4b2bc96f4858832ddef2f39f21e30b7226bbcd3c4b2bc96CNA
Linux23721387c409087fd3b97e274f34d3ddc0970b74 – < 2f55b58b5a0bbed192d60c444a45a49cdf1b545f2f55b58b5a0bbed192d60c444a45a49cdf1b545fCNA
Linux23721387c409087fd3b97e274f34d3ddc0970b74 – < 7962b522222628596ca9ecc8722efc95367aadbd7962b522222628596ca9ecc8722efc95367aadbdCNA
Linux23721387c409087fd3b97e274f34d3ddc0970b74 – < 4dee4c0688443aaf5bbec74aa203c851d1d53c354dee4c0688443aaf5bbec74aa203c851d1d53c35CNA
Linux23721387c409087fd3b97e274f34d3ddc0970b74 – < 1f2dc36c297d27733f1b380ea644cf15a361bd7b1f2dc36c297d27733f1b380ea644cf15a361bd7bCNA
Linux23721387c409087fd3b97e274f34d3ddc0970b74 – < 82d8701b2c930d0e96b0dbc9115a218d791cb0d282d8701b2c930d0e96b0dbc9115a218d791cb0d2CNA
Linux3.5–CNA

Scores by source

Linux (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refgit.kernel.org/stable/c/5202f071b367ffbc8e279fc7a00db14f5e587f52refgit.kernel.org/stable/c/69d1ce9c72eca91203ffdb8d08bacd511100aec6refgit.kernel.org/stable/c/f4858832ddef2f39f21e30b7226bbcd3c4b2bc96refgit.kernel.org/stable/c/2f55b58b5a0bbed192d60c444a45a49cdf1b545frefgit.kernel.org/stable/c/7962b522222628596ca9ecc8722efc95367aadbdrefgit.kernel.org/stable/c/4dee4c0688443aaf5bbec74aa203c851d1d53c35refgit.kernel.org/stable/c/1f2dc36c297d27733f1b380ea644cf15a361bd7brefgit.kernel.org/stable/c/82d8701b2c930d0e96b0dbc9115a218d791cb0d2