CVE-2021-3491
Linux kernel io_uring PROVIDE_BUFFERS MAX_RW_COUNT bypass
- State
- Published
- Severity
- 7.8 High
- Published
- Jun 4, 2021
- Updated
- Sep 16, 2024
- Reserved
- Apr 9, 2021
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).
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.8 High | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H | canonical |
Weaknesses
- CWE-131 Incorrect Calculation of Buffer Size
Affected Products
| Product | Versions |
|---|---|
Linux kernelLinux |
|
References
- https://ubuntu.com/security/notices/USN-4950-1vendor-advisory
- https://ubuntu.com/security/notices/USN-4949-1vendor-advisory
- [oss-security] CVE-2021-3491 - Linux kernel io_uring PROVIDE_BUFFERS MAX_RW_COUNT bypassmailing-list
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d1f82808877bb10d3deee7cf3374a4eb3fb582db
- https://www.zerodayinitiative.com/advisories/ZDI-21-589/
- https://security.netapp.com/advisory/ntap-20210716-0004/
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