CVE-2026-46040

inotify: fix watch count leak when fsnotify_add_inode_mark_locked() fails

MEDIUM
5.5
CVSS Score
Published: May 27, 2026 at 12:56 PM UTC
Updated: October 15, 2026 at 02:19 AM UTC
4 products affected across 2 vendorsLinux KernelSIMATIC S7-1500 CPU 1518-4 Pn /dp MFP FirmwareSiplus S7-1500 CPU 1518-4 Pn /dp MFP Firmware

Using Linux by Linux?

Get instant alerts when new vulnerabilities affect Linux - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM5.5
Exploit prediction
EPSS 0.1%

Description

In the Linux kernel, the following vulnerability has been resolved: inotify: fix watch count leak when fsnotify_add_inode_mark_locked() fails When fsnotify_add_inode_mark_locked() fails in inotify_new_watch(), the error path calls inotify_remove_from_idr() but does not call dec_inotify_watches() to undo the preceding inc_inotify_watches(). This leaks a watch count, and repeated failures can exhaust the max_user_watches limit with -ENOSPC even when no watches are active. Prior to commit 1cce1eea0aff ("inotify: Convert to using per-namespace limits"), the watch count was incremented after fsnotify_add_mark_locked() succeeded, so this path was not affected. The conversion moved inc_inotify_watches() before the mark insertion without adding the corresponding rollback. Add the missing dec_inotify_watches() call in the error path.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

4.11 ≤ v < 5.10.2585.11 ≤ v < 5.15.2095.16 ≤ v < 6.1.1756.13 ≤ v < 6.18.276.19 ≤ v < 7.0.46.2 ≤ v < 6.6.1406.7 ≤ v < 6.12.861cce1eea0aff51201753fcaca421df825b0813b64.11
Vendor states this is fixed in 10edf7e0ffdc7faa18e2244b17722c1b882b8273 (fixed)
Vendor states this is fixed in 3ab58cf42c46bf2366d2f55ae5c59299d5e178b7 (fixed)
Vendor states this is fixed in 3ad9ccea1b25435f6179b57aa891960beb7ce8f9 (fixed)
Vendor states this is fixed in 6a320935fa4293e9e599ec9f85dc9eb3be7029f8 (fixed)
Vendor states this is fixed in 73ddc8518a32baff6bc17afda4ee1ebae5b4ed12 (fixed)
Vendor states this is fixed in 8bcc1cd237ab5ccfdd102869fa031c541943cf40 (fixed)
Vendor states this is fixed in 9e48844f708eb48bae4e79cb21edc097c966306d (fixed)
Vendor states this is fixed in fdaa42ca370d056428e5e171247c8fdce8dff36a (fixed)
Vendor states this is fixed in 4.11 (unaffected)
Vendor states this is fixed in 5.10.258 (unaffected)
Vendor states this is fixed in 5.15.209 (unaffected)
Vendor states this is fixed in 6.1.175 (unaffected)
Vendor states this is fixed in 6.12.86 (unaffected)
Vendor states this is fixed in 6.18.27 (unaffected)
Vendor states this is fixed in 6.6.140 (unaffected)
Vendor states this is fixed in 7.0.4 (unaffected)
Vendor states this is fixed in 7.1 (unaffected)

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
NVD-CWE-Other

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card