CVE-2021-3491CWE-131

Linux kernel io_uring PROVIDE_BUFFERS MAX_RW_COUNT bypass

High · published June 4, 2021

CVSS v3.1
7.8
EPSS
1%
Percentile
50.3
In the wild
Unconfirmed
What it is

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).

The record
Technical detail
CVSS v3.1
7.8 · HIGH
Vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00644 · 50.3th percentile
Weakness
CWE-131 · Incorrect Calculation of Buffer Size
Published
2021-06-04T01:40Z
EPSS history
Timeline
  • 04 JUN 01:40Z
    Linux kernel io_uring PROVIDE_BUFFERS MAX_RW_COUNT bypass
    cvelistv5