What is CVE-2025-39963?

CVE-2025-39963 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10, classified as a Memory Leak flaw (CWE-401), affecting Linux kernel versions from 6.10 onward and patched in 6.12.49, 6.16.9 and 6.17. CVE-2025-39963 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-39963?

CVE-2025-39963 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-2025-39963?

Yes, CVE-2025-39963 has been patched. Fixed versions include 6.12.49, 6.16.9 and 6.17. If you are running Linux kernel 6.10 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-39963 actively exploited?

CVE-2025-39963 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-2025-39963

High

In the Linux kernel, the following vulnerability has been resolved: io_uring: fix incorrect io_kiocb reference in io_link_skb In io_link_skb function, there is a bug where prev_notif is incorrectly assigned using 'nd' instead of 'prev_nd'. This causes the context validation check to compare the current notification with itself instead of comparing it with the previous notification. Fix by using the correct prev_nd parameter when obtaining prev_notif.

Package Linux Kernel

Published 2025-10-09

Last modified 2026-02-26

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-401

CVE-2025-39963 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 6.10 and later are affected. Fixed in 6.12.49, 6.16.9, 6.17 and their respective stable series.

Affected from

≥ 6.10

Fixed in

✓ 6.12.49 6.12.x ✓ 6.16.9 6.16.x ✓ 6.17

References

The following references provide additional information about CVE-2025-39963 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/2c139a47eff8de24e3350dadb4c9d5e3426db826
Patch
Kernel patch commit
https://git.kernel.org/stable/c/50a98ce1ea694f1ff8e87bc2f8f84096d1736f6a
Patch
Kernel patch commit
https://git.kernel.org/stable/c/a89c34babc2e5834aa0905278f26f4dbe4b26b76
Patch

Details

CVE ID CVE-2025-39963

Severity High

CVSS score 7.8 / 10

CVSS version 3.1

Published 2025-10-09

Modified 2026-02-26

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-39963?

CVE-2025-39963 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 , classified as a Memory Leak flaw (CWE-401) . It affects Linux kernel versions from 6.10 onward and has been patched in 6.12.49, 6.16.9 and 6.17. CVE-2025-39963 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-39963?

CVE-2025-39963 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-2025-39963?

Yes — CVE-2025-39963 has been patched. Fixed versions include 6.12.49, 6.16.9 and 6.17. If you are running Linux kernel 6.10 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-39963 actively exploited?

No — CVE-2025-39963 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.
What is Memory Leak (CWE-401)?

The product does not release memory after use, causing gradual resource exhaustion. View CWE-401 on MITRE CWE →