CVE-2026-31657

batman-adv: hold claim backbone gateways by reference

State: Published
Severity: 9.8 Critical
Published: Apr 24, 2026
Updated: Oct 19, 2026
Reserved: Mar 9, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	9.8 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

CWE-416 Use After Free

Affected Products

Product	Versions
LinuxLinux	23721387c409087fd3b97e274f34d3ddc0970b74 to before 5202f071b367ffbc8e279fc7a00db14f5e587f52Affected 23721387c409087fd3b97e274f34d3ddc0970b74 to before 69d1ce9c72eca91203ffdb8d08bacd511100aec6Affected 23721387c409087fd3b97e274f34d3ddc0970b74 to before f4858832ddef2f39f21e30b7226bbcd3c4b2bc96Affected 23721387c409087fd3b97e274f34d3ddc0970b74 to before 2f55b58b5a0bbed192d60c444a45a49cdf1b545fAffected 23721387c409087fd3b97e274f34d3ddc0970b74 to before 7962b522222628596ca9ecc8722efc95367aadbdAffected 23721387c409087fd3b97e274f34d3ddc0970b74 to before 4dee4c0688443aaf5bbec74aa203c851d1d53c35Affected 23721387c409087fd3b97e274f34d3ddc0970b74 to before 1f2dc36c297d27733f1b380ea644cf15a361bd7bAffected 23721387c409087fd3b97e274f34d3ddc0970b74 to before 82d8701b2c930d0e96b0dbc9115a218d791cb0d2Affected
LinuxLinux	3.5Affected before 3.5Not affected 5.10.258 through 5.10.Not affected 5.15.209 through 5.15.Not affected 6.1.169 through 6.1.Not affected 6.6.135 through 6.6.Not affected 6.12.82 through 6.12.Not affected 6.18.23 through 6.18.Not affected 6.19.13 through 6.19.*Not affected 7.0 and laterNot affected

Product

Versions

LinuxLinux

23721387c409087fd3b97e274f34d3ddc0970b74 to before 5202f071b367ffbc8e279fc7a00db14f5e587f52Affected
23721387c409087fd3b97e274f34d3ddc0970b74 to before 69d1ce9c72eca91203ffdb8d08bacd511100aec6Affected
23721387c409087fd3b97e274f34d3ddc0970b74 to before f4858832ddef2f39f21e30b7226bbcd3c4b2bc96Affected
23721387c409087fd3b97e274f34d3ddc0970b74 to before 2f55b58b5a0bbed192d60c444a45a49cdf1b545fAffected
23721387c409087fd3b97e274f34d3ddc0970b74 to before 7962b522222628596ca9ecc8722efc95367aadbdAffected
23721387c409087fd3b97e274f34d3ddc0970b74 to before 4dee4c0688443aaf5bbec74aa203c851d1d53c35Affected
23721387c409087fd3b97e274f34d3ddc0970b74 to before 1f2dc36c297d27733f1b380ea644cf15a361bd7bAffected
23721387c409087fd3b97e274f34d3ddc0970b74 to before 82d8701b2c930d0e96b0dbc9115a218d791cb0d2Affected

LinuxLinux

3.5Affected
before 3.5Not affected
5.10.258 through 5.10.*Not affected
5.15.209 through 5.15.*Not affected
6.1.169 through 6.1.*Not affected
6.6.135 through 6.6.*Not affected
6.12.82 through 6.12.*Not affected
6.18.23 through 6.18.*Not affected
6.19.13 through 6.19.*Not affected
7.0 and laterNot affected

References

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