Medium · published May 27, 2026
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.
| Product | Versions | Fixed in |
|---|---|---|
| linux/linux_kernel | ≥ 4.11, < 5.10.258 | 5.10.258 |
| linux/linux_kernel | ≥ 5.11, < 5.15.209 | 5.15.209 |
| linux/linux_kernel | ≥ 5.16, < 6.1.175 | 6.1.175 |
| linux/linux_kernel | ≥ 6.2, < 6.6.140 | 6.6.140 |
| linux/linux_kernel | ≥ 6.7, < 6.12.86 | 6.12.86 |
| linux/linux_kernel | ≥ 6.13, < 6.18.27 | 6.18.27 |
| linux/linux_kernel | ≥ 6.19, < 7.0.4 | 7.0.4 |