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CVE-2021-3491

Linux kernel io_uring PROVIDE_BUFFERS MAX_RW_COUNT bypass

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in v5.13-rc4, v5.12.4, v5.11.21, v5.10.37
None on Exploit-DB, Metasploit or GitHub

Summary

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).

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux kernel

    From trunk · fixed in v5.13-rc4; From linux-5.12.y · fixed in v5.12.4; From linux-5.11.y · fixed in v5.11.21; From linux-5.10.y · fixed in v5.10.37; From v5.7-rc1

References 6

ubuntu.com

openwall.com

git.kernel.org

zerodayinitiative.com

security.netapp.com