What is CVE-2025-39943?

CVE-2025-39943 is a High severity Linux kernel vulnerability with a CVSS score of 7.1 out of 10, classified as a Out-of-bounds Read flaw (CWE-125), affecting Linux kernel versions from 5.15 onward and patched in 5.15.194, 6.1.154, 6.6.108 and others. CVE-2025-39943 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-39943?

CVE-2025-39943 has a CVSS score of 7.1 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:N/A:H.

Is there a patch available for CVE-2025-39943?

Yes, CVE-2025-39943 has been patched. Fixed versions include 5.15.194, 6.1.154, 6.6.108 and others. If you are running Linux kernel 5.15 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-39943 actively exploited?

CVE-2025-39943 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Out-of-bounds Read (CWE-125)?

The product reads data past the end or before the beginning of the intended buffer. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/125.html

CVE-2025-39943

High

In the Linux kernel, the following vulnerability has been resolved: ksmbd: smbdirect: validate data_offset and data_length field of smb_direct_data_transfer If data_offset and data_length of smb_direct_data_transfer struct are invalid, out of bounds issue could happen. This patch validate data_offset and data_length field in recv_done.

Package Linux Kernel

Published 2025-10-04

Last modified 2026-04-06

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.1

out of 10

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

High

Vector string

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

Weakness type

CWE-125

CVE-2025-39943 is a Out-of-bounds Read vulnerability

What is Out-of-bounds Read?

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

Affected versions

Linux kernel versions 5.15 and later are affected. Fixed in 5.15.194, 6.1.154, 6.6.108, 6.12.49, 6.16.9, 6.17 and their respective stable series.

Affected from

≥ 5.15

Fixed in

✓ 5.15.194 5.15.x ✓ 6.1.154 6.1.x ✓ 6.6.108 6.6.x ✓ 6.12.49 6.12.x ✓ 6.16.9 6.16.x ✓ 6.17

References

6 total

Kernel Git
https://git.kernel.org/stable/c/5282491fc49d5614ac6ddcd012e5743eecb6a67c

Patch
Kernel Git
https://git.kernel.org/stable/c/529b121b00a6ee3c88fb3c01b443b2b81f686d48

Patch
Kernel Git
https://git.kernel.org/stable/c/773fddf976d282ef059c36c575ddb81567acd6bc

Patch
Kernel Git
https://git.kernel.org/stable/c/8be498fcbd5b07272f560b45981d4b9e5a2ad885

Patch
Kernel Git
https://git.kernel.org/stable/c/bdaab5c6538e250a9654127e688ecbbeb6f771d5

Patch

Showing 5 of 6 references View all on NVD

Details

CVE ID CVE-2025-39943

Severity High

CVSS score 7.1 / 10

CVSS version 3.1

Published 2025-10-04

Modified 2026-04-06

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-39943?

CVE-2025-39943 is a High severity Linux kernel vulnerability with a CVSS score of 7.1 out of 10 , classified as an Out-of-bounds Read flaw (CWE-125) . It affects Linux kernel versions from 5.15 onward and has been patched in 5.15.194, 6.1.154, 6.6.108 and others. CVE-2025-39943 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-39943?

CVE-2025-39943 has a CVSS score of 7.1 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:N/A:H.
Is there a patch available for CVE-2025-39943?

Yes. CVE-2025-39943 has been patched. Fixed versions include 5.15.194, 6.1.154, 6.6.108 and others. If you are running Linux kernel 5.15 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-39943 actively exploited?

No. CVE-2025-39943 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.