Out-of-bounds Write Affecting torvalds/linux package, versions [5.7,5.10.37)[5.11,5.11.21)[5.12,5.12.4)


Severity

Recommended
0.0
high
0
10

CVSS assessment made by Snyk's Security Team. Learn more

Threat Intelligence

Exploit Maturity
Proof of Concept
EPSS
0.01% (1st percentile)

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  • Snyk IDSNYK-UNMANAGED-TORVALDSLINUX-3005145
  • published26 Jan 2022
  • disclosed4 Jun 2021
  • creditUnknown

Introduced: 4 Jun 2021

CVE-2021-3491  (opens in a new tab)
CWE-787  (opens in a new tab)

How to fix?

Upgrade torvalds/linux to version 5.10.37, 5.11.21, 5.12.4 or higher.

Overview

Affected versions of this package are vulnerable to Out-of-bounds Write. 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//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).

References

CVSS Base Scores

version 3.1