What is CVE-2025-21768?

CVE-2025-21768 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, classified as a Memory Leak flaw (CWE-401), affecting Linux kernel versions from 4.10 onward and patched in 6.12.16, 6.13.4 and 6.14. CVE-2025-21768 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-21768?

CVE-2025-21768 has a CVSS score of 5.5 out of 10, rated Medium severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2025-21768?

Yes, CVE-2025-21768 has been patched. Fixed versions include 6.12.16, 6.13.4 and 6.14. If you are running Linux kernel 4.10 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-21768 actively exploited?

CVE-2025-21768 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Memory Leak (CWE-401)?

The product does not release memory after use, causing gradual resource exhaustion. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/401.html

CVE-2025-21768

Medium

In the Linux kernel, the following vulnerability has been resolved: net: ipv6: fix dst ref loops in rpl, seg6 and ioam6 lwtunnels Some lwtunnels have a dst cache for post-transformation dst. If the packet destination did not change we may end up recording a reference to the lwtunnel in its own cache, and the lwtunnel state will never be freed. Discovered by the ioam6.sh test, kmemleak was recently fixed to catch per-cpu memory leaks. I'm not sure if rpl and seg6 can actually hit this, but in principle I don't see why not.

Package Linux Kernel

Published 2025-02-27

Last modified 2025-10-28

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

5.5

out of 10

Medium

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

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

Weakness type

CWE-401

CVE-2025-21768 is a Memory Leak vulnerability

What is Memory Leak?

The product does not release memory after use, causing gradual resource exhaustion. Learn more on MITRE CWE

Affected versions

Linux kernel versions 4.10 and later are affected. Fixed in 6.12.16, 6.13.4, 6.14 and their respective stable series.

Affected from

≥ 4.10

Fixed in

✓ 6.12.16 6.12.x ✓ 6.13.4 6.13.x ✓ 6.14

References

3 total

Kernel Git
https://git.kernel.org/stable/c/4c0f200c7d06fedddde82209c099014d63f4a6c0

Patch
Kernel Git
https://git.kernel.org/stable/c/5ab11a4e219e93b8b31a27f8ec98d42afadd8b7a

Patch
Kernel Git
https://git.kernel.org/stable/c/92191dd1073088753821b862b791dcc83e558e07

Patch

Details

CVE ID CVE-2025-21768

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2025-02-27

Modified 2025-10-28

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-21768?

CVE-2025-21768 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as a Memory Leak flaw (CWE-401) . It affects Linux kernel versions from 4.10 onward and has been patched in 6.12.16, 6.13.4 and 6.14. CVE-2025-21768 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-21768?

CVE-2025-21768 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2025-21768?

Yes. CVE-2025-21768 has been patched. Fixed versions include 6.12.16, 6.13.4 and 6.14. If you are running Linux kernel 4.10 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-21768 actively exploited?

No. CVE-2025-21768 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.