Skip to content
7.8 High

CVE-2021-3491 The io_uring subsystem in the Linux kernel allowed the MAX_RW_COUNT limit to be bypassed in the PROVIDE_BUFFERS…

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 products and versions

Product Affected versions Fixed in
Linux Kernel 5.13 earliest → < 5.13-rc4 5.13-rc4
Linux Kernel 5.12 earliest → < 5.12.4 5.12.4
Linux Kernel 5.11 earliest → < 5.11.21 5.11.21
Linux Kernel 5.10 earliest → < 5.10.37 5.10.37
Linux Kernel 5.7 5.7-rc1 → latest No fix stated

References

Timeline

  1. Published
  2. Last modified
The 43 CVEs of Linux Kernel →
Track this CVE