CVE-2026-46040
inotify: fix watch count leak when fsnotify_add_inode_mark_locked() fails
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.
INFO
Published Date :
May 27, 2026, 2:17 p.m.
Last Modified :
June 1, 2026, 5:17 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel to the latest version.
- Verify the patch addresses the watch count leak.
- Monitor user watch limits after applying updates.
References to Advisories, Solutions, and Tools
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CVE-2026-46040.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-46040 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
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stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-46040
weaknesses.
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The following table lists the changes that have been made to the
CVE-2026-46040 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jun. 01, 2026
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/10edf7e0ffdc7faa18e2244b17722c1b882b8273 Added Reference https://git.kernel.org/stable/c/3ab58cf42c46bf2366d2f55ae5c59299d5e178b7 Added Reference https://git.kernel.org/stable/c/3ad9ccea1b25435f6179b57aa891960beb7ce8f9 -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 27, 2026
Action Type Old Value New Value Added 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. Added Reference https://git.kernel.org/stable/c/6a320935fa4293e9e599ec9f85dc9eb3be7029f8 Added Reference https://git.kernel.org/stable/c/73ddc8518a32baff6bc17afda4ee1ebae5b4ed12 Added Reference https://git.kernel.org/stable/c/8bcc1cd237ab5ccfdd102869fa031c541943cf40 Added Reference https://git.kernel.org/stable/c/9e48844f708eb48bae4e79cb21edc097c966306d Added Reference https://git.kernel.org/stable/c/fdaa42ca370d056428e5e171247c8fdce8dff36a