CVE-2025-39899 Affecting kernel-default-vdso package, versions <6.12.0-160000.6.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.02% (6th percentile)

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  • Snyk IDSNYK-SLES1600-KERNELDEFAULTVDSO-13941392
  • published14 Nov 2025
  • disclosed6 Nov 2025

Introduced: 6 Nov 2025

NewCVE-2025-39899  (opens in a new tab)

How to fix?

Upgrade SLES:16.0.0 kernel-default-vdso to version 6.12.0-160000.6.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-default-vdso package and not the kernel-default-vdso package as distributed by SLES. See How to fix? for SLES:16.0.0 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

mm/userfaultfd: fix kmap_local LIFO ordering for CONFIG_HIGHPTE

With CONFIG_HIGHPTE on 32-bit ARM, move_pages_pte() maps PTE pages using kmap_local_page(), which requires unmapping in Last-In-First-Out order.

The current code maps dst_pte first, then src_pte, but unmaps them in the same order (dst_pte, src_pte), violating the LIFO requirement. This causes the warning in kunmap_local_indexed():

WARNING: CPU: 0 PID: 604 at mm/highmem.c:622 kunmap_local_indexed+0x178/0x17c addr != __fix_to_virt(FIX_KMAP_BEGIN + idx)

Fix this by reversing the unmap order to respect LIFO ordering.

This issue follows the same pattern as similar fixes:

  • commit eca6828403b8 ("crypto: skcipher - fix mismatch between mapping and unmapping order")
  • commit 8cf57c6df818 ("nilfs2: eliminate staggered calls to kunmap in nilfs_rename")

Both of which addressed the same fundamental requirement that kmap_local operations must follow LIFO ordering.

CVSS Base Scores

version 3.1