PT-2026-35009 · Linux · Linux Kernel

Published 2026-04-24 · Updated 2026-05-03 · CVE-2026-31657

Positive Technologies (AI Summary)

CVSS v3.1

9.8

Critical

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description In the batman-adv module, the function batadv bla add claim() can replace claim->backbone gw and drop the last reference of the old gateway while readers are still following 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. Additionally, the function batadv bla check claim() utilizes the same naked pointer access pattern.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

NULL Pointer Dereference

Weakness Enumeration

CWE-476

Related Identifiers

CVE-2026-31657

ECHO-3B89-A04B-E497

Affected Products

Linux Kernel

References · 17

• https://git.kernel.org/stable/c/4dee4c0688443aaf5bbec74aa203c851d1d53c35 · Patch
• https://osv.dev/vulnerability/BELL-CVE-2026-31657 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2026-31657 · Vendor Advisory
• https://git.kernel.org/stable/c/7962b522222628596ca9ecc8722efc95367aadbd · Patch
• https://git.kernel.org/stable/c/f4858832ddef2f39f21e30b7226bbcd3c4b2bc96 · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-31657 · Security Note
• https://git.kernel.org/stable/c/82d8701b2c930d0e96b0dbc9115a218d791cb0d2 · Patch
• https://ubuntu.com/security/CVE-2026-31657 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-31657 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-31657 · Vendor Advisory
• https://git.kernel.org/stable/c/2f55b58b5a0bbed192d60c444a45a49cdf1b545f · Patch
• https://git.kernel.org/stable/c/1f2dc36c297d27733f1b380ea644cf15a361bd7b · Patch
• https://cve.org/CVERecord?id=CVE-2026-31657 · Security Note
• https://git.kernel.org/linus/82d8701b2c930d0e96b0dbc9115a218d791cb0d2 · Note
• https://t.me/msrcreports/4053 · Telegram Post