Critical 9.8Published Apr 24, 2026

CVE-2026-31657batman-adv: hold claim backbone gateways by reference

Updated under an hour ago (Oct 28, 2026, 5:40 AM ET)

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Exploited in the last 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.

CVSS: 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-416
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	23721387c409087fd3b97e274f34d3ddc0970b74 builds before 5202f071b367ffbc8e279fc7a00db14f5e587f52; 23721387c409087fd3b97e274f34d3ddc0970b74 builds before 69d1ce9c72eca91203ffdb8d08bacd511100aec6; from 23721387c409087fd3b97e274f34d3ddc0970b74 before f4858832ddef2f39f21e30b7226bbcd3c4b2bc96; 23721387c409087fd3b97e274f34d3ddc0970b74 builds before 2f55b58b5a0bbed192d60c444a45a49cdf1b545f; 23721387c409087fd3b97e274f34d3ddc0970b74 builds before 7962b522222628596ca9ecc8722efc95367aadbd; 23721387c409087fd3b97e274f34d3ddc0970b74 builds before 4dee4c0688443aaf5bbec74aa203c851d1d53c35; 23721387c409087fd3b97e274f34d3ddc0970b74 builds before 1f2dc36c297d27733f1b380ea644cf15a361bd7b; 23721387c409087fd3b97e274f34d3ddc0970b74 builds before 82d8701b2c930d0e96b0dbc9115a218d791cb0d2	CNA record
linux linux_kernel linux:linux_kernel	from 3.5.1 before 6.1.169; from 6.2 before 6.6.135; from 6.7 before 6.12.82; from 6.13 before 6.18.23; from 6.19 before 6.19.13; 3.5; 7.0; 7.0; and 5 more ranges	NVD

References

References

https://git.kernel.org/stable/c/5202f071b367ffbc8e279fc7a00db14f5e587f52
https://git.kernel.org/stable/c/69d1ce9c72eca91203ffdb8d08bacd511100aec6
https://git.kernel.org/stable/c/f4858832ddef2f39f21e30b7226bbcd3c4b2bc96	patch
https://git.kernel.org/stable/c/2f55b58b5a0bbed192d60c444a45a49cdf1b545f	patch
https://git.kernel.org/stable/c/7962b522222628596ca9ecc8722efc95367aadbd	patch
https://git.kernel.org/stable/c/4dee4c0688443aaf5bbec74aa203c851d1d53c35	patch
https://git.kernel.org/stable/c/1f2dc36c297d27733f1b380ea644cf15a361bd7b	patch
https://git.kernel.org/stable/c/82d8701b2c930d0e96b0dbc9115a218d791cb0d2	patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.