CVE-2021-3491
kernel: Linux kernel io_uring PROVIDE_BUFFERS MAX_RW_COUNT bypass
Severity
ImportantRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · May 11, 2021
Updated · November 22, 2025
Description
A flaw was found in the Linux kernel. The io_uring PROVIDE_BUFFERS operation allowed the MAX_RW_COUNT limit to be bypassed, which led to negative values being used in mem_rw when reading /proc/<PID>/mem. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 7.4CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE-119 · Improper Restriction of Operations within the Bounds of a Memory Buffer