{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "7.1.2"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "9a07d0b8214ac4e8e10c23fce71d613bd0625524"
            }
          ],
          "repo": "https://github.com/zammad/zammad",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-m9ff-hjr3-93h4"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-290",
      "CWE-295",
      "CWE-347"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/84xxx/CVE-2026-84465.json"
  },
  "details": "Zammad is a web based open source helpdesk/customer support system. Prior to 7.1.2, when Zammad checks the digital signature on an incoming S/MIME-signed email, it does not verify that the signing certificate is genuinely trusted, it only checks whether a certificate with a matching name is already stored in the system. An attacker can create their own certificate using the name of a real, previously trusted sender and use it to send a forged email. Zammad will display that email with the same \"validly signed\" indicator as a genuine message from the real sender, even though the attacker never had access to that sender's actual certificate or private key. This issue is fixed in version 7.1.2.",
  "id": "CVE-2026-84465",
  "modified": "2026-09-27T03:30:41.280863747Z",
  "published": "2026-09-25T18:19:58.735Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/84xxx/CVE-2026-84465.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/zammad/zammad/security/advisories/GHSA-m9ff-hjr3-93h4"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-84465"
    },
    {
      "type": "FIX",
      "url": "https://github.com/zammad/zammad/commit/9a07d0b8214ac4e8e10c23fce71d613bd0625524"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Zammad: S/MIME signature verification allows forged sender impersonation"
}