CVE-2025-39840 (GCVE-0-2025-39840)
Vulnerability from cvelistv5
Published
2025-09-19 15:26
Modified
2025-09-29 06:00
Severity ?
Summary
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]
References
Impacted products
Vendor Product Version
Linux Linux Version: e92eebb0d6116f942ab25dfb1a41905aa59472a8
Version: e92eebb0d6116f942ab25dfb1a41905aa59472a8
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/auditfilter.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "9735a9dcc307427e7d6336c54171682f1bac9789",
              "status": "affected",
              "version": "e92eebb0d6116f942ab25dfb1a41905aa59472a8",
              "versionType": "git"
            },
            {
              "lessThan": "4540f1d23e7f387880ce46d11b5cd3f27248bf8d",
              "status": "affected",
              "version": "e92eebb0d6116f942ab25dfb1a41905aa59472a8",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/auditfilter.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "lessThan": "6.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.16.*",
              "status": "unaffected",
              "version": "6.16.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.17",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.16.6",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.17",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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]"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-09-29T06:00:45.574Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/9735a9dcc307427e7d6336c54171682f1bac9789"
        },
        {
          "url": "https://git.kernel.org/stable/c/4540f1d23e7f387880ce46d11b5cd3f27248bf8d"
        }
      ],
      "title": "audit: fix out-of-bounds read in audit_compare_dname_path()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-39840",
    "datePublished": "2025-09-19T15:26:15.596Z",
    "dateReserved": "2025-04-16T07:20:57.141Z",
    "dateUpdated": "2025-09-29T06:00:45.574Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-39840\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-09-19T16:15:42.703\",\"lastModified\":\"2025-09-22T21:23:01.543\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"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]\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/4540f1d23e7f387880ce46d11b5cd3f27248bf8d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/9735a9dcc307427e7d6336c54171682f1bac9789\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.