linux-cve-announce - CVE-2025-68788: fsnotify: do not generate ACCESS/MODIFY events on child for special files

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <2026011303-CVE-2025-68788-05bd@gregkh>
Date: Tue, 13 Jan 2026 16:29:14 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-68788: fsnotify: do not generate ACCESS/MODIFY events on child for special files

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

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

fsnotify: do not generate ACCESS/MODIFY events on child for special files

inotify/fanotify do not allow users with no read access to a file to
subscribe to events (e.g. IN_ACCESS/IN_MODIFY), but they do allow the
same user to subscribe for watching events on children when the user
has access to the parent directory (e.g. /dev).

Users with no read access to a file but with read access to its parent
directory can still stat the file and see if it was accessed/modified
via atime/mtime change.

The same is not true for special files (e.g. /dev/null). Users will not
generally observe atime/mtime changes when other users read/write to
special files, only when someone sets atime/mtime via utimensat().

Align fsnotify events with this stat behavior and do not generate
ACCESS/MODIFY events to parent watchers on read/write of special files.
The events are still generated to parent watchers on utimensat(). This
closes some side-channels that could be possibly used for information
exfiltration [1].

[1] https://snee.la/pdf/pubs/file-notification-attacks.pdf

The Linux kernel CVE team has assigned CVE-2025-68788 to this issue.

Affected and fixed versions
===========================

	Fixed in 6.1.160 with commit 6a7d7d96eeeab7af2bd01afbb3d9878a11a13d91
	Fixed in 6.6.120 with commit e0643d46759db8b84c0504a676043e5e341b6c81
	Fixed in 6.12.64 with commit 82f7416bcbd951549e758d15fc1a96a5afc2e900
	Fixed in 6.18.3 with commit 7a93edb23bcf07a3aaf8b598edfc2faa8fbcc0b6
	Fixed in 6.19-rc2 with commit 635bc4def026a24e071436f4f356ea08c0eed6ff

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-68788
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	fs/notify/fsnotify.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/6a7d7d96eeeab7af2bd01afbb3d9878a11a13d91
	https://git.kernel.org/stable/c/e0643d46759db8b84c0504a676043e5e341b6c81
	https://git.kernel.org/stable/c/82f7416bcbd951549e758d15fc1a96a5afc2e900
	https://git.kernel.org/stable/c/7a93edb23bcf07a3aaf8b598edfc2faa8fbcc0b6
	https://git.kernel.org/stable/c/635bc4def026a24e071436f4f356ea08c0eed6ff