CVE-2025-39816
MEDIUM EPSS 3.3%
Published Sep 16, 20259mo ago · Modified Jun 17, 20261w ago
5.5 CVSS 3.1
Published Sep 16, 2025 9mo ago
Last Modified Jun 17, 2026 1w ago
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.
CVSS Details
Base Score
Exploitability
Impact
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High
Threat Intelligence
EPSS Exploit Probability
3.3% percentile
Exploit & Patch Status
No Known Exploit
Patch Available
Affected Products 5
References 4
- git.kernel.org https://git.kernel.org/stable/c/390a61d284e1ced088d43928dfcf6f86fffdd780
- git.kernel.org https://git.kernel.org/stable/c/695673eb5711ee5eb1769481cf1503714716a7d1
- git.kernel.org https://git.kernel.org/stable/c/91f262ea2a76a02d9e37dba6637cfe6feebb20a8
- git.kernel.org https://git.kernel.org/stable/c/98b6fa62c84f2e129161e976a5b9b3cb4ccd117b
Remediation
- git.kernel.org https://git.kernel.org/stable/c/390a61d284e1ced088d43928dfcf6f86fffdd780
- git.kernel.org https://git.kernel.org/stable/c/695673eb5711ee5eb1769481cf1503714716a7d1
- git.kernel.org https://git.kernel.org/stable/c/98b6fa62c84f2e129161e976a5b9b3cb4ccd117b