What is CVE-2025-39856?

CVE-2025-39856 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, classified as a NULL Pointer Dereference flaw (CWE-476), affecting Linux kernel versions from 6.15 onward and patched in 6.16.6 and 6.17. CVE-2025-39856 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-39856?

CVE-2025-39856 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-2025-39856?

Yes, CVE-2025-39856 has been patched. Fixed versions include 6.16.6 and 6.17. If you are running Linux kernel 6.15 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-39856 actively exploited?

CVE-2025-39856 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is NULL Pointer Dereference (CWE-476)?

The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/476.html

CVE-2025-39856

Medium

In the Linux kernel, the following vulnerability has been resolved: net: ethernet: ti: am65-cpsw-nuss: Fix null pointer dereference for ndev In the TX completion packet stage of TI SoCs with CPSW2G instance, which has single external ethernet port, ndev is accessed without being initialized if no TX packets have been processed. It results into null pointer dereference, causing kernel to crash. Fix this by having a check on the number of TX packets which have been processed.

Package Linux Kernel

Published 2025-09-19

Last modified 2026-01-14

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-476

CVE-2025-39856 is a NULL Pointer Dereference vulnerability

What is NULL Pointer Dereference?

The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. Learn more on MITRE CWE

Affected versions

Linux kernel versions 6.15 and later are affected. Fixed in 6.16.6, 6.17 and their respective stable series.

Affected from

≥ 6.15

Fixed in

✓ 6.16.6 6.16.x ✓ 6.17

References

The following references provide additional information about CVE-2025-39856 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/485302905bada953aadfe063320d73c892a66cbb
Patch
Kernel patch commit
https://git.kernel.org/stable/c/a6099f263e1f408bcc7913c9df24b0677164fc5d
Patch

Details

CVE ID CVE-2025-39856

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2025-09-19

Modified 2026-01-14

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-39856?

CVE-2025-39856 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as a NULL Pointer Dereference flaw (CWE-476) . It affects Linux kernel versions from 6.15 onward and has been patched in 6.16.6 and 6.17. CVE-2025-39856 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-39856?

CVE-2025-39856 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-2025-39856?

Yes — CVE-2025-39856 has been patched. Fixed versions include 6.16.6 and 6.17. If you are running Linux kernel 6.15 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-39856 actively exploited?

No — CVE-2025-39856 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.
What is NULL Pointer Dereference (CWE-476)?

The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. View CWE-476 on MITRE CWE →