PT-2025-49064 · Linux+2 · Linux Kernel+2

Published

2025-10-01

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Updated

2026-05-07

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CVE-2025-40237

CVSS v2.0

5.0

Medium

VectorAV:L/AC:H/Au:S/C:P/I:P/A:C
Name of the Vulnerable Software and Affected Versions Linux kernel versions prior to 6.17.0-rc6
Description The Linux kernel contains a flaw within the fs/notify subsystem. Specifically, calling inotify show fdinfo() on a file descriptor watching an overlayfs inode during unmounting can lead to a dereference of a NULL pointer. This occurs when exportfs encode fid() is called with s umount, potentially causing a general protection fault. The issue arises because ovl check encode origin dereferences inode->i sb->s root after it has been set to NULL during the unmount process. The fix involves protecting calls to exportfs encode fid() from show mark fhandle() using the s umount lock.
Recommendations Update to a version newer than 6.17.0-rc6.

Exploit

Fix

NULL Pointer Dereference

Weakness Enumeration

CWE-476

Related Identifiers

BDU:2026-02798
CVE-2025-40237
OESA-2026-1759
OESA-2026-1760
OESA-2026-1761
OPENSUSE-SU-2026:20145-1
SUSE-SU-2026:20207-1
SUSE-SU-2026:20220-1
SUSE-SU-2026:20228-1
USN-8029-1
USN-8029-2
USN-8029-3
USN-8030-1
USN-8048-1
USN-8095-1
USN-8095-2
USN-8095-3
USN-8095-4
USN-8095-5
USN-8100-1
USN-8125-1
USN-8126-1
USN-8165-1
USN-8261-1

Affected Products

Linuxmint
Linux Kernel
Ubuntu