CVE-2025-39827: Debian Linux

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: net: rose: include node references in rose_neigh refcount Current implementation maintains two separate reference counting mechanisms: the 'count' field in struct rose_neigh tracks references from rose_node structures, while the 'use' field (now refcount_t) tracks references from rose_sock. This patch merges these two reference counting systems using 'use' field for proper reference management. Specifically, this patch adds incrementing and decrementing of rose_neigh->use when rose_neigh->count is incremented or decremented. This patch also modifies rose_rt_free(), rose_rt_device_down() and rose_clear_route() to properly release references to rose_neigh objects before freeing a rose_node through rose_remove_node(). These changes ensure rose_neigh structures are properly freed only when all references, including those from rose_node structures, are released. As a result, this resolves a slab-use-after-free issue reported by Syzbot.

Affected products

• Debian Debian Linux: version 11.0 only
• Linux Linux Kernel: from 2.6.12.1, before 6.1.150 (fixed in 6.1.150); from 6.2, before 6.6.104 (fixed in 6.6.104); from 6.7, before 6.12.45 (fixed in 6.12.45); from 6.13, before 6.16.5 (fixed in 6.16.5); version 2.6.12 only; version 6.17 only

Published 2025-09-16. Last modified 2026-07-30.