In the Linux kernel, the following vulnerability has been resolved: io_uring/kbuf: always use READ_ONCE() to read ring provided buffer lengths Since the buffers are mapped from userspace, it is prudent to use READ_ONCE() to read the value into a local variable, and use that for any other actions taken. Having a stable read of the buffer length avoids worrying about it changing after checking, or being read multiple times. Similarly, the buffer may well change in between it being picked and being committed. Ensure the looping for incremental ring buffer commit stops if it hits a zero sized buffer, as no further progress can be made at that point.
History

Wed, 17 Sep 2025 11:00:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Vendors & Products Linux
Linux linux Kernel

Wed, 17 Sep 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Tue, 16 Sep 2025 13:15:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: io_uring/kbuf: always use READ_ONCE() to read ring provided buffer lengths Since the buffers are mapped from userspace, it is prudent to use READ_ONCE() to read the value into a local variable, and use that for any other actions taken. Having a stable read of the buffer length avoids worrying about it changing after checking, or being read multiple times. Similarly, the buffer may well change in between it being picked and being committed. Ensure the looping for incremental ring buffer commit stops if it hits a zero sized buffer, as no further progress can be made at that point.
Title io_uring/kbuf: always use READ_ONCE() to read ring provided buffer lengths
References

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2025-09-16T13:00:17.026Z

Updated: 2025-09-16T13:00:17.026Z

Reserved: 2025-04-16T07:20:57.138Z

Link: CVE-2025-39816

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2025-09-16T13:15:56.790

Modified: 2025-09-16T13:15:56.790

Link: CVE-2025-39816

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-09-16T00:00:00Z

Links: CVE-2025-39816 - Bugzilla