CVE-2025-39826: net: rose: convert 'use' field to refcount_t

Severity: high (CVSS 7.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-09-16 · updated 2026-10-19
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: net: rose: convert 'use' field to refcount_t The 'use' field in struct rose_neigh is used as a reference counter but lacks atomicity. This can lead to race conditions where a rose_neigh structure is freed while still being referenced by other code paths. For example, when rose_neigh->use becomes zero during an ioctl operation via rose_rt_ioctl(), the structure may be removed while its timer is still active, potentially causing use-after-free issues. This patch changes the type of 'use' from unsigned short to refcount_t and updates all code paths to use rose_neigh_hold() and rose_neigh_put() which operate reference counts atomically.

Affected products

Debian Linux: 11.0
Linux kernel: from 2.6.12.1 before 6.1.150; from 6.2 before 6.6.104; from 6.7 before 6.12.45; from 6.13 before 6.16.5; 2.6.12, 2.6.12-rc2, 2.6.12-rc3, 2.6.12-rc4, 2.6.12-rc5, 6.17-rc1 (+2) — fixed in 6.1.150, 6.12.45, 6.16.5, 6.6.104

How to fix

Upgrade to a fixed version: Linux kernel 6.1.150, 6.12.45, 6.16.5, 6.6.104. Check the vendor advisory for mitigations.

References

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