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]
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 19 Sep 2025 15:30:00 +0000

Type Values Removed Values Added
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]
Title audit: fix out-of-bounds read in audit_compare_dname_path()
References

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-09-19T15:26:15.596Z

Reserved: 2025-04-16T07:20:57.141Z

Link: CVE-2025-39840

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2025-09-19T16:15:42.703

Modified: 2025-09-19T16:15:42.703

Link: CVE-2025-39840

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.