How severe is CVE-2021-3491?

This vulnerability has a severity rating of HIGH with a CVSS score of 8.8 out of 10.

What type of vulnerability is CVE-2021-3491?

This is classified as CWE-131, which is a common weakness in software security.

CVE-2021-3491 - HIGH Severity | CVSS 8.8

Vulnerability 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).

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