CVE-2026-52928

Analyzed Analyzed - Analysis Complete

AF_UNIX SIOCATMARK Rejection on Non-Stream Sockets

Publication date: 2026-06-24

Last updated on: 2026-07-08

Assigner: kernel.org

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.

CVSS Scores

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Meta Information

Published

2026-06-24

Last Modified

2026-07-08

Generated

2026-07-15

AI Q&A

2026-06-24

EPSS Evaluated

2026-07-14

NVD

CVE-2026-52928

EUVD

EUVD-2026-38698

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	7.1
linux	linux_kernel	7.1
linux	linux_kernel	From 6.13 (inc) to 6.18.30 (exc)
linux	linux_kernel	From 6.19 (inc) to 7.0.7 (exc)
linux	linux_kernel	From 6.7 (inc) to 6.12.88 (exc)
linux	linux_kernel	From 5.16 (inc) to 6.1.177 (exc)
linux	linux_kernel	From 6.2 (inc) to 6.6.144 (exc)
linux	linux_kernel	From 5.15 (inc) to 5.15.211 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability exists in the Linux kernel's AF_UNIX socket implementation. Specifically, the issue involves the handling of the SIOCATMARK ioctl command, which is used to determine if the receive queue is at the urgent mark for out-of-band data (MSG_OOB).

In AF_UNIX sockets, MSG_OOB is only supported for SOCK_STREAM sockets. However, SOCK_DGRAM and SOCK_SEQPACKET sockets reject MSG_OOB in sendmsg() and recvmsg(), so they should also reject SIOCATMARK. The vulnerability was that SIOCATMARK was not properly rejected on non-stream sockets, potentially allowing incorrect behavior.

The fix was to return an error code (-EOPNOTSUPP) for non-stream sockets before checking the receive queue, ensuring that SIOCATMARK is only supported on appropriate socket types.

Impact Analysis

This vulnerability could lead to improper handling of socket operations on non-stream AF_UNIX sockets. Since SIOCATMARK is not supposed to be supported on these socket types, allowing it could cause unexpected behavior or errors in applications relying on socket communication.

While the exact impact depends on how software uses these socket types, it could potentially result in application crashes, incorrect data processing, or security issues related to socket communication.

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