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]

CVSS Metrics

• v3.1•HIGH•Score: 7.1CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

EPSS Trends

Current EPSS score: 0.02%• Percentile: 6%

Techniques & Countermeasures

• CWE-125•Out-of-bounds Read

  The product reads data past the end, or before the beginning, of the intended buffer.

Affected Systems

• linux•linux

  ≥ e92eebb0d6116f942ab25dfb1a41905aa59472a8, < 9735a9dcc307427e7d6336c54171682f1bac9789 | ≥ e92eebb0d6116f942ab25dfb1a41905aa59472a8, < 4540f1d23e7f387880ce46d11b5cd3f27248bf8d | 6.14

• linux•linux_kernel

  ≥ 6.14, < 6.16.6 | 6.17:rc1 | 6.17:rc2 | 6.17:rc3 | 6.17:rc4

References (2)

• https://git.kernel.org/stable/c/9735a9dcc307427e7d6336c54171682f1bac9789
• https://git.kernel.org/stable/c/4540f1d23e7f387880ce46d11b5cd3f27248bf8d