What is CVE-2025-39815?

CVE-2025-39815 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, affecting Linux kernel versions from 6.8 onward and patched in 6.12.45, 6.16.5 and 6.17. CVE-2025-39815 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-39815?

CVE-2025-39815 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-2025-39815?

Yes, CVE-2025-39815 has been patched. Fixed versions include 6.12.45, 6.16.5 and 6.17. If you are running Linux kernel 6.8 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-39815 actively exploited?

CVE-2025-39815 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2025-39815

Medium

In the Linux kernel, the following vulnerability has been resolved: RISC-V: KVM: fix stack overrun when loading vlenb The userspace load can put up to 2048 bits into an xlen bit stack buffer. We want only xlen bits, so check the size beforehand.

Package Linux Kernel

Published 2025-09-16

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

Affected versions

Linux kernel versions 6.8 and later are affected. Fixed in 6.12.45, 6.16.5, 6.17 and their respective stable series.

Affected from

≥ 6.8

Fixed in

✓ 6.12.45 6.12.x ✓ 6.16.5 6.16.x ✓ 6.17

References

The following references provide additional information about CVE-2025-39815 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/6d28659b692a0212f360f8bd8a58712b339f9aac
Patch
Kernel patch commit
https://git.kernel.org/stable/c/799766208f09f95677a9ab111b93872d414fbad7
Patch
Kernel patch commit
https://git.kernel.org/stable/c/c76bf8359188a11f8fd790e5bbd6077894a245cc
Patch

Details

CVE ID CVE-2025-39815

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2025-09-16

Modified 2026-01-14

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-39815?

CVE-2025-39815 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 6.8 onward and has been patched in 6.12.45, 6.16.5 and 6.17. CVE-2025-39815 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-39815?

CVE-2025-39815 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-2025-39815?

Yes — CVE-2025-39815 has been patched. Fixed versions include 6.12.45, 6.16.5 and 6.17. If you are running Linux kernel 6.8 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-39815 actively exploited?

No — CVE-2025-39815 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.