CVE-2021-3491

HIGH

Linux Kernel 5.7-5.10.37 - Heap Overflow via io_uring PROVIDE_BUFFERS Operation

Title source: llm
STIX 2.1

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).

References (6)

Core 6
Core References
Third Party Advisory vendor-advisory x_refsource_ubuntu
https://ubuntu.com/security/notices/USN-4950-1
Third Party Advisory vendor-advisory x_refsource_ubuntu
https://ubuntu.com/security/notices/USN-4949-1
Mailing List, Patch, Third Party Advisory mailing-list x_refsource_mlist
https://www.openwall.com/lists/oss-security/2021/05/11/13
Third Party Advisory, VDB Entry x_refsource_misc
https://www.zerodayinitiative.com/advisories/ZDI-21-589/
Third Party Advisory x_refsource_confirm
https://security.netapp.com/advisory/ntap-20210716-0004/

Scores

CVSS v3 7.8
EPSS 0.0063
EPSS Percentile 45.2%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Details

CWE
CWE-131 CWE-787
Status published
Products (4)
canonical/ubuntu_linux 20.04
canonical/ubuntu_linux 20.10
canonical/ubuntu_linux 21.04
linux/linux_kernel 5.7 - 5.10.37
Published Jun 04, 2021
Tracked Since Feb 18, 2026