PT-2025-6932 · Linux+8 · Linux Kernel+8

Mikołaj Lenczewski

+1

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Published

2025-01-12

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Updated

2026-05-26

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CVE-2025-21696

CVSS v3.1

5.5

Medium

VectorAV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Name of the Vulnerable Software and Affected Versions: Linux kernel (affected versions not specified)
Description: The issue arises when a memory region previously registered with userfaultfd as write-protected but without UFFD FEATURE EVENT REMAP is mremap()ed, leading to an inconsistency in flag clearing. This inconsistency causes a mismatch between the vma flags and the pte/pmd flags, resulting in a warning when setting the pte to writable while uffd-wp is still set. The fix involves explicitly clearing the uffd-wp pte/pmd flags on any such mremap() to ensure consistent values with the existing clearing of VM UFFD WP.
Recommendations: At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

RCE

Weakness Enumeration

Related Identifiers

ALSA-2025:20095
ALSA-2025:20518
ALT-PU-2025-12647
ALT-PU-2025-3467
AZL-56839
BDU:2025-15320
CVE-2025-21696
ECHO-39E1-BA56-3347
INFSA-2025_20518
OPENSUSE-SU-2025_01614-1
OPENSUSE-SU-2025_01707-1
RHSA-2025:20095
RHSA-2025:20518
RHSA-2025_20518
SUSE-SU-2025:01614-1
SUSE-SU-2025:01707-1
SUSE-SU-2025:01919-1
SUSE-SU-2025:01951-1
SUSE-SU-2025:01964-1
SUSE-SU-2025:01967-1
SUSE-SU-2025:20343-1
SUSE-SU-2025:20344-1
SUSE-SU-2025:20354-1
SUSE-SU-2025:20355-1
SUSE-SU-2025_01614-1
SUSE-SU-2025_01707-1
SUSE-SU-2025_01951-1
SUSE-SU-2025_01964-1
SUSE-SU-2025_01967-1
USN-7445-1
USN-7448-1

Affected Products

Alt Linux
Almalinux
Debian
Linuxmint
Linux Kernel
Red Hat
Rocky Linux
Suse
Ubuntu