CVE-2021-3491

Severity CVSS v4.0:

Pending analysis

Type:

CWE-787 Out-of-bounds Write

Publication date:

04/06/2021

Last modified:

14/09/2021

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//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).

Impact

Vector 3.x

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H CVSS v3.1 Severity and Metrics:

Base Score: 8.80 HIGH
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Changed
Confidentiality (C): High
Integrity (I): High
Availability (A): High

Base Score 3.x

8.80

Severity 3.x

HIGH

Vector 2.0

AV:L/AC:L/Au:N/C:C/I:C/A:C CVSS v2.0 Severity and Metrics:

Base Score: 7.20 HIGH
Vector: AV:L/AC:L/Au:N/C:C/I:C/A:C

Attack Vector (AV): Local
Attack Complexity (AC): Low
Authentication (Au): None
Confidentiality (C): Complete
Integrity (I): Complete
Availability (A): Complete

Base Score 2.0

7.20

Severity 2.0

HIGH

Vulnerable products and versions

CPE	From	Up to
cpe:2.3:o:linux:linux_kernel::::::::	5.7 (including)	5.10.37 (excluding)
cpe:2.3:o:linux:linux_kernel::::::::	5.11 (including)	5.11.21 (excluding)
cpe:2.3:o:linux:linux_kernel::::::::	5.12 (including)	5.12.4 (excluding)
cpe:2.3:o:canonical:ubuntu_linux:20.04::::lts:::
cpe:2.3:o:canonical:ubuntu_linux:20.10:::::::*
cpe:2.3:o:canonical:ubuntu_linux:21.04:::::::*

To consult the complete list of CPE names with products and versions, see this page

CVE-2021-3491

Description

Impact

Vulnerable products and versions

References to Advisories, Solutions, and Tools