CVE-2025-39725

Medium

In the Linux kernel, the following vulnerability has been resolved: mm/vmscan: fix hwpoisoned large folio handling in shrink_folio_list In shrink_folio_list(), the hwpoisoned folio may be large folio, which can't be handled by unmap_poisoned_folio(). For THP, try_to_unmap_one() must be passed with TTU_SPLIT_HUGE_PMD to split huge PMD first and then retry. Without TTU_SPLIT_HUGE_PMD, we will trigger null-ptr deref of pvmw.pte. Even we passed TTU_SPLIT_HUGE_PMD, we will trigger a WARN_ON_ONCE due to the page isn't in swapcache. Since UCE is rare in real world, and race with reclaimation is more rare, just skipping the hwpoisoned large folio is enough. memory_failure() will handle it if the UCE is triggered again. This happens when memory reclaim for large folio races with memory_failure(), and will lead to kernel panic. The race is as follows: cpu0 cpu1 shrink_folio_list memory_failure TestSetPageHWPoison unmap_poisoned_folio --> trigger BUG_ON due to unmap_poisoned_folio couldn't handle large folio [[email protected]: add comment to unmap_poisoned_folio()]

Package Linux Kernel
Published 2025-09-05
Last modified 2025-11-25
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-2025-39725 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 6.12.26, 6.14.5, 6.15 and later are affected. Fixed in 6.12.41, 6.15.9, 6.16 and their respective stable series.

Affected from
≥ 6.12.26 ≥ 6.14.5 ≥ 6.15
Fixed in
✓ 6.12.41 6.12.x ✓ 6.15.9 6.15.x ✓ 6.16

References

The following references provide additional information about CVE-2025-39725 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Frequently asked questions

  • What is CVE-2025-39725?

    CVE-2025-39725 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 6.12.26 onward and has been patched in 6.12.41, 6.15.9 and 6.16. CVE-2025-39725 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2025-39725?

    CVE-2025-39725 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-2025-39725?

    Yes — CVE-2025-39725 has been patched. Fixed versions include 6.12.41, 6.15.9 and 6.16. If you are running Linux kernel 6.12.26 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2025-39725 actively exploited?

    No — CVE-2025-39725 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 →

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