CVE-2026-31657
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.4% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.4% in the next 30 days (EPSS).
- Severity: 9.8 CRITICAL (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.4% · EPSS, next 30 days
- Weakness
- CWE-476 · NULL pointer dereference
- Record status
- Modified
Affected
- Linux Kernel < 6.1.169
- Linux Kernel < 6.6.135
- Linux Kernel < 6.12.82
- Linux Kernel < 6.18.23
- Linux Kernel < 6.19.13
- Linux Kernel 3.5
- Linux Kernel 7.0
Attack profile CVSS 3.1 · 9.8
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-31657.md and follow it. Check whether this project is affected by CVE-2026-31657. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/1f2dc36c297d27733f1b380ea644cf15a361bd7b
- https://git.kernel.org/stable/c/2f55b58b5a0bbed192d60c444a45a49cdf1b545f
- https://git.kernel.org/stable/c/4dee4c0688443aaf5bbec74aa203c851d1d53c35
- https://git.kernel.org/stable/c/7962b522222628596ca9ecc8722efc95367aadbd
- https://git.kernel.org/stable/c/82d8701b2c930d0e96b0dbc9115a218d791cb0d2
- https://git.kernel.org/stable/c/f4858832ddef2f39f21e30b7226bbcd3c4b2bc96
References
- https://git.kernel.org/stable/c/1f2dc36c297d27733f1b380ea644cf15a361bd7b
- https://git.kernel.org/stable/c/2f55b58b5a0bbed192d60c444a45a49cdf1b545f
- https://git.kernel.org/stable/c/4dee4c0688443aaf5bbec74aa203c851d1d53c35
- https://git.kernel.org/stable/c/5202f071b367ffbc8e279fc7a00db14f5e587f52
- https://git.kernel.org/stable/c/69d1ce9c72eca91203ffdb8d08bacd511100aec6
- https://git.kernel.org/stable/c/7962b522222628596ca9ecc8722efc95367aadbd
- https://git.kernel.org/stable/c/82d8701b2c930d0e96b0dbc9115a218d791cb0d2
- https://git.kernel.org/stable/c/f4858832ddef2f39f21e30b7226bbcd3c4b2bc96