What is CVE-2021-3491?

CVE-2021-3491 is a High severity Linux kernel vulnerability with a CVSS score of 8.8 out of 10, affecting Linux kernel versions from trunk onward and patched in v5.13-rc4, v5.12.4, v5.11.21 and others. CVE-2021-3491 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2021-3491?

CVE-2021-3491 has a CVSS score of 8.8 out of 10, rated High severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

Is there a patch available for CVE-2021-3491?

Yes, CVE-2021-3491 has been patched. Fixed versions include v5.13-rc4, v5.12.4, v5.11.21 and others. If you are running Linux kernel trunk or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2021-3491 actively exploited?

CVE-2021-3491 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2021-3491

High

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).

Package Linux Kernel

Published 2021-06-04

Last modified 2024-11-21

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

8.8

out of 10

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Vector string

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Weakness type

CWE-131

CVE-2021-3491 is classified as CWE-131

See CWE-131 on MITRE CWE for full details on this weakness type.

Affected versions

Linux kernel versions trunk, linux-5.12.y, linux-5.11.y, linux-5.10.y, v5.7-rc1 and later are affected. Fixed in v5.13-rc4, v5.12.4, v5.11.21, v5.10.37, 5.7* and their respective stable series.

Affected from

≥ trunk ≥ linux-5.12.y ≥ linux-5.11.y ≥ linux-5.10.y ≥ v5.7-rc1

Fixed in

✓ v5.13-rc4 ✓ v5.12.4 v5.12.x ✓ v5.11.21 v5.11.x ✓ v5.10.37 v5.10.x ✓ 5.7*

References

6 total

Kernel Git
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d1f82808877bb10d3deee7cf3374a4eb3fb582db

Patch Vendor Advisory
Openwall
https://www.openwall.com/lists/oss-security/2021/05/11/13

Mailing List Patch Third Party Advisory
Security
https://security.netapp.com/advisory/ntap-20210716-0004/

Third Party Advisory
Ubuntu Security
https://ubuntu.com/security/notices/USN-4949-1

Third Party Advisory
Ubuntu Security
https://ubuntu.com/security/notices/USN-4950-1

Third Party Advisory

Showing 5 of 6 references View all on NVD

Details

CVE ID CVE-2021-3491

Severity High

CVSS score 8.8 / 10

CVSS version 3.1

Published 2021-06-04

Modified 2024-11-21

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2021-3491?

CVE-2021-3491 is a High severity Linux kernel vulnerability with a CVSS score of 8.8 out of 10 . It affects Linux kernel versions from trunk onward and has been patched in v5.13-rc4, v5.12.4, v5.11.21 and others. CVE-2021-3491 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2021-3491?

CVE-2021-3491 has a CVSS score of 8.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.
Is there a patch available for CVE-2021-3491?

Yes. CVE-2021-3491 has been patched. Fixed versions include v5.13-rc4, v5.12.4, v5.11.21 and others. If you are running Linux kernel trunk or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2021-3491 actively exploited?

No. CVE-2021-3491 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.