Critical severity · published Apr 24, 2026
CVE-2026-31657
batman-adv: hold claim backbone gateways by reference
9.8
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 34% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
3.5.1 before 6.1.169; 6.2 before 6.6.135; 6.7 before 6.12.82; 6.13 before 6.18.23; 6.19 before 6.19.13; 3.5; +7 more · source: NVD
LI
Linux · Linux
23721387c409087fd3b97e274f34d3ddc0970b74 before 5202f071b367ffbc8e279fc7a00db14f5e587f52; 23721387c409087fd3b97e274f34d3ddc0970b74 before 69d1ce9c72eca91203ffdb8d08bacd511100aec6; 23721387c409087fd3b97e274f34d3ddc0970b74 before f4858832ddef2f39f21e30b7226bbcd3c4b2bc96; 23721387c409087fd3b97e274f34d3ddc0970b74 before 2f55b58b5a0bbed192d60c444a45a49cdf1b545f; 23721387c409087fd3b97e274f34d3ddc0970b74 before 7962b522222628596ca9ecc8722efc95367aadbd; 23721387c409087fd3b97e274f34d3ddc0970b74 before 4dee4c0688443aaf5bbec74aa203c851d1d53c35; +3 more · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-31657
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-31657
Patch
https://git.kernel.org/stable/c/1f2dc36c297d27733f1b380ea644cf15a361bd7b
Patch
https://git.kernel.org/stable/c/2f55b58b5a0bbed192d60c444a45a49cdf1b545f
Patch
https://git.kernel.org/stable/c/4dee4c0688443aaf5bbec74aa203c851d1d53c35
git.kernel.org
https://git.kernel.org/stable/c/5202f071b367ffbc8e279fc7a00db14f5e587f52
git.kernel.org
https://git.kernel.org/stable/c/69d1ce9c72eca91203ffdb8d08bacd511100aec6
Patch
https://git.kernel.org/stable/c/7962b522222628596ca9ecc8722efc95367aadbd
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