What is CVE-2025-21671?

CVE-2025-21671 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10, classified as a Use After Free flaw (CWE-416), affecting Linux kernel versions from 6.1.122 onward and patched in 6.1.127, 6.6.74 and 6.12.11. CVE-2025-21671 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-21671?

CVE-2025-21671 has a CVSS score of 7.8 out of 10, rated High severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2025-21671?

Yes, CVE-2025-21671 has been patched. Fixed versions include 6.1.127, 6.6.74 and 6.12.11. If you are running Linux kernel 6.1.122 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-21671 actively exploited?

CVE-2025-21671 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Use After Free (CWE-416)?

The product references memory after it has been freed, which may cause it to crash, use unexpected values, or execute code. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/416.html

CVE-2025-21671

High

In the Linux kernel, the following vulnerability has been resolved: zram: fix potential UAF of zram table If zram_meta_alloc failed early, it frees allocated zram->table without setting it NULL. Which will potentially cause zram_meta_free to access the table if user reset an failed and uninitialized device.

Package Linux Kernel

Published 2025-01-31

Last modified 2025-11-03

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.8

out of 10

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

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

Weakness type

CWE-416

CVE-2025-21671 is a Use After Free vulnerability

What is Use After Free?

The product references memory after it has been freed, which may cause it to crash, use unexpected values, or execute code. Learn more on MITRE CWE

Affected versions

Linux kernel versions 6.1.122, 6.6.68, 6.12.7 and later are affected. Fixed in 6.1.127, 6.6.74, 6.12.11 and their respective stable series.

Affected from

≥ 6.1.122 ≥ 6.6.68 ≥ 6.12.7

Fixed in

✓ 6.1.127 6.1.x ✓ 6.6.74 6.6.x ✓ 6.12.11 6.12.x

References

5 total

Kernel Git
https://git.kernel.org/stable/c/212fe1c0df4a150fb6298db2cfff267ceaba5402

Patch
Kernel Git
https://git.kernel.org/stable/c/571d3f6045cd3a6d9f6aec33b678f3ffe97582ef

Patch
Kernel Git
https://git.kernel.org/stable/c/902ef8f16d5ca77edc77c30656be54186c1e99b7

Patch
Kernel Git
https://git.kernel.org/stable/c/fe3de867f94819ba0f28e035c0b0182150147d95

Patch
Debian Security
https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html

Details

CVE ID CVE-2025-21671

Severity High

CVSS score 7.8 / 10

CVSS version 3.1

Published 2025-01-31

Modified 2025-11-03

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-21671?

CVE-2025-21671 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 , classified as an Use After Free flaw (CWE-416) . It affects Linux kernel versions from 6.1.122 onward and has been patched in 6.1.127, 6.6.74 and 6.12.11. CVE-2025-21671 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-21671?

CVE-2025-21671 has a CVSS score of 7.8 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:U/C:H/I:H/A:H.
Is there a patch available for CVE-2025-21671?

Yes. CVE-2025-21671 has been patched. Fixed versions include 6.1.127, 6.6.74 and 6.12.11. If you are running Linux kernel 6.1.122 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-21671 actively exploited?

No. CVE-2025-21671 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.