Security advisory

{
  "id": "daf5e5af62d8b9c247a6bee0ed87b3f0a76692fbfcfb9062110290e27e12286d",
  "url": "https://osv.dev/vulnerability/CVE-2018-12551",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2018-12551",
    "summary": "When Eclipse Mosquitto version 1.0 to 1.5.5 (inclusive) is configured to use a password file for authentication, any malformed data in the password file will be treated as valid. This typically means that the malformed data becomes a username and no password. If this occurs, clients can circumvent authentication and get access to the broker by using the malformed username. In particular, a blank line will be treated as a valid empty username. Other security measures are unaffected. Users who have only used the mosquitto_passwd utility to create and modify their password files are unaffected by this vulnerability.",
    "evidence": "osv:CVE-2018-12551",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2018-12551",
      "aliases": [
        "CVE-2018-12551"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/eclipse-mosquitto/mosquitto",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "66dfa573946425661626e2f574ef125ab01b01f5"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:eclipse:mosquitto:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.0"
                      },
                      {
                        "last_affected": "1.5.5"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.5.5",
            "v1.5.4",
            "v1.5.3",
            "v1.5.2",
            "v1.5.1",
            "v1.5",
            "v1.4.15",
            "v1.4.14",
            "v1.4.13",
            "v1.4.12",
            "v1.4.11",
            "v1.4.10",
            "v1.4.9",
            "v1.4.8",
            "v1.4.7",
            "v1.4.6",
            "v1.4.5",
            "v1.4.4",
            "v1.4.3",
            "v1.4.2",
            "v1.4.1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-12551.json"
          }
        }
      ],
      "modified": "2026-10-24T10:30:52.891798799Z",
      "provider": "osv",
      "references": [
        "https://lists.debian.org/debian-lts-announce/2019/10/msg00035.html",
        "https://bugs.eclipse.org/bugs/show_bug.cgi?id=543401"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2018-12551",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 437794,
  "published_at": "2019-03-27T18:29:00.367+00:00"
}