What is CVE-2025-21927?

CVE-2025-21927 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10, classified as a Out-of-bounds Write flaw (CWE-787), affecting Linux kernel versions from 5.0 onward and patched in 6.12.19, 6.13.7 and 6.14. CVE-2025-21927 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-21927?

CVE-2025-21927 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-2025-21927?

Yes, CVE-2025-21927 has been patched. Fixed versions include 6.12.19, 6.13.7 and 6.14. If you are running Linux kernel 5.0 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-21927 actively exploited?

CVE-2025-21927 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Out-of-bounds Write (CWE-787)?

The product writes data past the end or before the beginning of the intended buffer. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/787.html

CVE-2025-21927

High

In the Linux kernel, the following vulnerability has been resolved: nvme-tcp: fix potential memory corruption in nvme_tcp_recv_pdu() nvme_tcp_recv_pdu() doesn't check the validity of the header length. When header digests are enabled, a target might send a packet with an invalid header length (e.g. 255), causing nvme_tcp_verify_hdgst() to access memory outside the allocated area and cause memory corruptions by overwriting it with the calculated digest. Fix this by rejecting packets with an unexpected header length.

Package Linux Kernel

Published 2025-04-01

Last modified 2025-10-01

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-787

CVE-2025-21927 is a Out-of-bounds Write vulnerability

What is Out-of-bounds Write?

The product writes data past the end or before the beginning of the intended buffer. Learn more on MITRE CWE

Affected versions

Linux kernel versions 5.0 and later are affected. Fixed in 6.12.19, 6.13.7, 6.14 and their respective stable series.

Affected from

≥ 5.0

Fixed in

✓ 6.12.19 6.12.x ✓ 6.13.7 6.13.x ✓ 6.14

References

The following references provide additional information about CVE-2025-21927 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Kernel patch commit
https://git.kernel.org/stable/c/22b06c89aa6b2d1ecb8aea72edfb9d53af8d5126
Patch
Kernel patch commit
https://git.kernel.org/stable/c/9fbc953d6b38bc824392e01850f0aeee3b348722
Patch
Kernel patch commit
https://git.kernel.org/stable/c/ad95bab0cd28ed77c2c0d0b6e76e03e031391064
Patch

Details

CVE ID CVE-2025-21927

Severity High

CVSS score 7.8 / 10

CVSS version 3.1

Published 2025-04-01

Modified 2025-10-01

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-21927?

CVE-2025-21927 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 , classified as an Out-of-bounds Write flaw (CWE-787) . It affects Linux kernel versions from 5.0 onward and has been patched in 6.12.19, 6.13.7 and 6.14. CVE-2025-21927 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-21927?

CVE-2025-21927 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-2025-21927?

Yes — CVE-2025-21927 has been patched. Fixed versions include 6.12.19, 6.13.7 and 6.14. If you are running Linux kernel 5.0 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-21927 actively exploited?

No — CVE-2025-21927 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.
What is Out-of-bounds Write (CWE-787)?

The product writes data past the end or before the beginning of the intended buffer. View CWE-787 on MITRE CWE →