Linux Kernel up to 6.19.12 batadv_bla_add_claim null pointer dereference

CVSS Meta Temp Score
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CTI Interest Score
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7.6$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.1.168/6.6.134/6.12.81/6.18.22/6.19.12. It has been classified as critical. Affected is the function batadv_bla_add_claim. This manipulation causes null pointer dereference. This vulnerability appears as CVE-2026-31657. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.1.168/6.6.134/6.12.81/6.18.22/6.19.12. It has been declared as critical. Affected by this vulnerability is the function batadv_bla_add_claim. The manipulation with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. As an impact it is known to affect availability. The summary by CVE 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.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2026-31657 since 03/09/2026. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 310309 (Linux Distros Unpatched Vulnerability : CVE-2026-31657), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.169, 6.6.135, 6.12.82, 6.18.23 or 6.19.13 eliminates this vulnerability. Applying the patch f4858832ddef2f39f21e30b7226bbcd3c4b2bc96/2f55b58b5a0bbed192d60c444a45a49cdf1b545f/7962b522222628596ca9ecc8722efc95367aadbd/4dee4c0688443aaf5bbec74aa203c851d1d53c35/1f2dc36c297d27733f1b380ea644cf15a361bd7b/82d8701b2c930d0e96b0dbc9115a218d791cb0d2 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (310309) and EUVD (EUVD-2026-25550). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.7
VulDB Meta Temp Score: 7.6

VulDB Base Score: 5.7
VulDB Temp Score: 5.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 9.8
CNA Vector (Linux): 🔒

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 310309
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-31657

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.169/6.6.135/6.12.82/6.18.23/6.19.13
Patch: f4858832ddef2f39f21e30b7226bbcd3c4b2bc96/2f55b58b5a0bbed192d60c444a45a49cdf1b545f/7962b522222628596ca9ecc8722efc95367aadbd/4dee4c0688443aaf5bbec74aa203c851d1d53c35/1f2dc36c297d27733f1b380ea644cf15a361bd7b/82d8701b2c930d0e96b0dbc9115a218d791cb0d2

Timelineinfo

03/09/2026 CVE reserved
04/24/2026 +45 days Advisory disclosed
04/24/2026 +0 days VulDB entry created
06/04/2026 +41 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-31657 (🔒)
GCVE (CVE): GCVE-0-2026-31657
GCVE (VulDB): GCVE-100-359413
EUVD: 🔒

Entryinfo

Created: 04/24/2026 17:59
Updated: 06/04/2026 05:06
Changes: 04/24/2026 17:59 (58), 04/24/2026 18:34 (1), 04/26/2026 14:23 (2), 06/04/2026 05:06 (11)
Complete: 🔍
Cache ID: 216::103

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