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Critical 9.8Published Apr 24, 2026

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

Updated under an hour ago ()

Does this affect you?

It affects Linux and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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)
Not given
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 16, 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

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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.

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