CVE-2025-39840
Description
In the Linux kernel, the following vulnerability has been resolved: audit: fix out-of-bounds read in audit_compare_dname_path() When a watch on dir=/ is combined with an fsnotify event for a single-character name directly under / (e.g., creating /a), an out-of-bounds read can occur in audit_compare_dname_path(). The helper parent_len() returns 1 for "/". In audit_compare_dname_path(), when parentlen equals the full path length (1), the code sets p = path + 1 and pathlen = 1 - 1 = 0. The subsequent loop then dereferences p[pathlen - 1] (i.e., p[-1]), causing an out-of-bounds read. Fix this by adding a pathlen > 0 check to the while loop condition to prevent the out-of-bounds access. [PM: subject tweak, sign-off email fixes]
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
AlmaLinux Fixed 1 release
| Version | Status | Fixed in |
|---|---|---|
| 9 | Fixed | kernel-doc-5.14.0-611.20.1.el9_7.noarch.rpm |
Debian Fixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 0 |
| sid | Fixed | 6.16.6-1 |
| forky | Fixed | 6.16.6-1 |
| bullseye | Fixed | 0 |
| bookworm | Fixed | 0 |
Red Hat Fixed 1 release
| Version | Status | Fixed in |
|---|---|---|
| 9 | Fixed | — |
Rocky Linux Fixed 1 release
| Version | Status | Fixed in |
|---|---|---|
| 9 | Fixed | — |
References
- https://access.redhat.com/errata/RHSA-2026:0445
- https://www.suse.com/security/cve/CVE-2025-39840.html
- https://errata.rockylinux.org/RLSA-2026:0445
- https://security-tracker.debian.org/tracker/CVE-2025-39840
- https://bugzilla.redhat.com/2395807
- https://bugzilla.redhat.com/2396936
- https://bugzilla.redhat.com/2397553
- https://bugzilla.redhat.com/2418832
- https://errata.almalinux.org/9/ALSA-2026-0445.html
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.