What is CVE-2025-39836?

CVE-2025-39836 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 6.8 onward and patched in 6.12.45, 6.16.5 and 6.17. CVE-2025-39836 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-39836?

CVE-2025-39836 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-2025-39836?

Yes, CVE-2025-39836 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-2025-39836 actively exploited?

CVE-2025-39836 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-2025-39836

High

In the Linux kernel, the following vulnerability has been resolved: efi: stmm: Fix incorrect buffer allocation method The communication buffer allocated by setup_mm_hdr() is later on passed to tee_shm_register_kernel_buf(). The latter expects those buffers to be contiguous pages, but setup_mm_hdr() just uses kmalloc(). That can cause various corruptions or BUGs, specifically since commit 9aec2fb0fd5e ("slab: allocate frozen pages"), though it was broken before as well. Fix this by using alloc_pages_exact() instead of kmalloc().

Package Linux Kernel

Published 2025-09-16

Last modified 2026-01-14

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-2025-39836 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 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-2025-39836 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/630c0e6064daf84f17aad1a7d9ca76b562e3fe47
Patch
Kernel patch commit
https://git.kernel.org/stable/c/77ff27ff0e4529a003c8a1c2492c111968c378d3
Patch
Kernel patch commit
https://git.kernel.org/stable/c/c5e81e672699e0c5557b2b755cc8f7a69aa92bff
Patch

Details

CVE ID CVE-2025-39836

Severity High

CVSS score 7.8 / 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-2025-39836?

CVE-2025-39836 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 6.8 onward and has been patched in 6.12.45, 6.16.5 and 6.17. CVE-2025-39836 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-39836?

CVE-2025-39836 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-2025-39836?

Yes — CVE-2025-39836 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-2025-39836 actively exploited?

No — CVE-2025-39836 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 →