GHSA-CWJM-393V-32X2
Vulnerability from github – Published: 2025-09-22 21:30 – Updated: 2025-12-12 21:31In 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]
{
"affected": [],
"aliases": [
"CVE-2025-39840"
],
"database_specific": {
"cwe_ids": [
"CWE-125"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-09-19T16:15:42Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\naudit: fix out-of-bounds read in audit_compare_dname_path()\n\nWhen a watch on dir=/ is combined with an fsnotify event for a\nsingle-character name directly under / (e.g., creating /a), an\nout-of-bounds read can occur in audit_compare_dname_path().\n\nThe helper parent_len() returns 1 for \"/\". In audit_compare_dname_path(),\nwhen parentlen equals the full path length (1), the code sets p = path + 1\nand pathlen = 1 - 1 = 0. The subsequent loop then dereferences\np[pathlen - 1] (i.e., p[-1]), causing an out-of-bounds read.\n\nFix this by adding a pathlen \u003e 0 check to the while loop condition\nto prevent the out-of-bounds access.\n\n[PM: subject tweak, sign-off email fixes]",
"id": "GHSA-cwjm-393v-32x2",
"modified": "2025-12-12T21:31:32Z",
"published": "2025-09-22T21:30:17Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-39840"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4540f1d23e7f387880ce46d11b5cd3f27248bf8d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9735a9dcc307427e7d6336c54171682f1bac9789"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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