CVE-2026-31657 Details
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.
A vulnerability in the Linux kernel's batman-adv module allows improper management of backbone gateway references. The issue arises because the function batadv_bla_add_claim() can replace a claim's backbone gateway and drop the last reference to the old gateway while other processes are still using it. This can lead to a situation where the netlink claim dump path accesses a dangling pointer, potentially causing a use-after-free error. The problem is exacerbated by batadv_bla_check_claim(), which also accesses pointers without proper validation. The vulnerability affects the Linux kernel stable tree.
Users can upgrade to the latest version of the Linux kernel where this vulnerability has been addressed. Instructions for upgrading the kernel can be found in the official Linux kernel documentation.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-476 | NULL Pointer Dereference | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 3.5.1, < 6.1.169 >= 6.2, < 6.6.135 >= 6.7, < 6.12.82 >= 6.13, < 6.18.23 >= 6.19, < 6.19.13 3.5 - 7.0 rc1 7.0 rc2 7.0 rc3 7.0 rc4 7.0 rc5 7.0 rc6 7.0 rc7 |
CPE
Remediation
| |
Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | kernel.org |
| Jun 1, 2026 | CVE Modified | kernel.org |
| Apr 27, 2026 | Initial Analysis | [email protected] |
| Apr 27, 2026 | CVE Modified | kernel.org |
| Apr 24, 2026 | New CVE Received | kernel.org |