VULNERABILITY INTELLIGENCE
CVE-2021-3491
CVSS score7.8 HIGH
EPSS probability0.64%
CISA KEVNot currently listed
Published2021-06-04
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Description
The io_uring subsystem in the Linux kernel allowed the MAX_RW_COUNT limit to be bypassed in the PROVIDE_BUFFERS operation, which led to negative values being usedin mem_rw when reading /proc/<PID>/mem. This could be used to create a heap overflow leading to arbitrary code execution in the kernel. It was addressed via commit d1f82808877b ("io_uring: truncate lengths larger than MAX_RW_COUNT on provide buffers") (v5.13-rc1) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. It was introduced in ddf0322db79c ("io_uring: add IORING_OP_PROVIDE_BUFFERS") (v5.7-rc1).
Weakness classification
- security@ubuntu.com: CWE-131
- nvd@nist.gov: CWE-787
Primary references
- security@ubuntu.com — Patch, Vendor Advisory
- security@ubuntu.com — Third Party Advisory
- security@ubuntu.com — Third Party Advisory
- security@ubuntu.com — Third Party Advisory
- security@ubuntu.com — Mailing List, Patch, Third Party Advisory
- security@ubuntu.com — Third Party Advisory, VDB Entry
- af854a3a-2127-422b-91ae-364da2661108 — Patch, Vendor Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Third Party Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Third Party Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Third Party Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Mailing List, Patch, Third Party Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Third Party Advisory, VDB Entry