libnginx-mod-http-cache-purge — security advisory

{
  "id": "e0cd24736f4cf70b0d543fae94a314f607b0f61854765624aba7811f09e613a1",
  "url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-108981",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "UBUNTU-CVE-2026-108981",
    "summary": "ngx_cache_purge before 3.0.4 can allow file deletion via a symlink attack in certain situations where nginx and a served application (e.g., WordPress) run under the same user account. The attacker must be able to create a symlink inside the cache path. Version 3.0.4 fixes this for the case of a symlink created at an arbitrary earlier time, but does not resolve an applicable TOCTOU race condition. (The ngx_cache_purge module follows symlinks while walking the cache directory tree during purge operations. The module relies on nginx's ngx_walk_tree(), which relies on stat() and therefore follows symlinks.)",
    "evidence": "osv:UBUNTU-CVE-2026-108981",
    "products": [
      {
        "name": {
          "value": "libnginx-mod-http-cache-purge",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1:2.3-5",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1:2.3-6",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1:2.3-6build2",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "libnginx-mod-http-cache-purge",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1:2.5.5-1build2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:2.5.6-1build1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:3.0.2-1",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "libnginx-mod-http-cache-purge",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1:2.5.3-3build1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1:2.5.4-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1:2.5.4-1build1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1:2.5.5-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1:2.5.5-1build1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1:2.5.5-1build2",
            "evidence": "/affected/2/versions"
          }
        ]
      }
    ],
    "severity": "low",
    "structured": {
      "id": "UBUNTU-CVE-2026-108981",
      "aliases": [
        "UBUNTU-CVE-2026-108981"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L"
        },
        {
          "type": "Ubuntu",
          "score": "medium"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "libnginx-mod-http-cache-purge",
            "purl": "pkg:deb/ubuntu/libnginx-mod-http-cache-purge?arch=source&distro=noble",
            "ecosystem": "Ubuntu:24.04:LTS"
          },
          "versions": [
            "1:2.3-5",
            "1:2.3-6",
            "1:2.3-6build2"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-108981.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "libnginx-mod-http-cache-purge",
                "binary_version": "1:2.3-6build2"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "libnginx-mod-http-cache-purge",
            "purl": "pkg:deb/ubuntu/libnginx-mod-http-cache-purge?arch=source&distro=stonking",
            "ecosystem": "Ubuntu:26.10"
          },
          "versions": [
            "1:2.5.5-1build2",
            "1:2.5.6-1build1",
            "1:3.0.2-1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-108981.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "libnginx-mod-http-cache-purge",
                "binary_version": "1:3.0.2-1"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "libnginx-mod-http-cache-purge",
            "purl": "pkg:deb/ubuntu/libnginx-mod-http-cache-purge?arch=source&distro=resolute",
            "ecosystem": "Ubuntu:26.04:LTS"
          },
          "versions": [
            "1:2.5.3-3build1",
            "1:2.5.4-1",
            "1:2.5.4-1build1",
            "1:2.5.5-1",
            "1:2.5.5-1build1",
            "1:2.5.5-1build2"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-108981.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "libnginx-mod-http-cache-purge",
                "binary_version": "1:2.5.5-1build2"
              }
            ]
          }
        }
      ],
      "modified": "2026-10-17T12:59:48.958212851Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-108981"
      ],
      "references": [
        "https://ubuntu.com/security/CVE-2026-108981",
        "https://www.cve.org/CVERecord?id=CVE-2026-108981",
        "https://github.com/nginx-modules/ngx_cache_purge/commit/a6da1352f52a8a02dd6828e88c39ed42fddcee96",
        "https://github.com/nginx-modules/ngx_cache_purge/pull/72",
        "https://github.com/nginx-modules/ngx_cache_purge/releases/tag/3.0.4"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-108981",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 359803,
  "published_at": "2026-10-12T03:17:00+00:00"
}