CVEvulnerability

CVE-2021-3491

8.8 HIGH Published 2021-06-04 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2021-06-04
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
7.8 HIGH — CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
CVSS 3.1 ([email protected])
8.8 HIGH — CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CVSS 2.0 ([email protected])
7.2 HIGH — AV:L/AC:L/Au:N/C:C/I:C/A:C
Weaknesses
CWE-131, CWE-787

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).

Affected configurations

• linux linux kernel (>= 5.7 < 5.10.37) • linux linux kernel (>= 5.11 < 5.11.21) • linux linux kernel (>= 5.12 < 5.12.4) • canonical ubuntu linux 20.04 • canonical ubuntu linux 20.10 • canonical ubuntu linux 21.04

Related

Weakness · CWE (2)

  • CWE-131 Incorrect Calculation of Buffer Size weakness
  • CWE-787 Out-of-bounds Write weakness

References