{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "1.2319"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "fb37bbfabf5e75d08f0cfa6ce9b84469d62a20a0"
            },
            {
              "fixed": "0b0fe9ac1cee98620f16aef85cebf67869ca41a8"
            }
          ],
          "repo": "https://github.com/m66b/fairemail",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-r8ff-qr7g-pvw6"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-79"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54521.json"
  },
  "details": "FairEmail is a fully featured, open source, privacy-friendly email app for Android. Prior to 1.2319, the ActivityAMP AMP message renderer in app/src/main/java/eu/faircode/email/ActivityAMP.java enables JavaScript in its WebView but incompletely sanitizes untrusted message HTML. For non-allowlisted hosts, script.removeAttr(\"src\") leaves inline script elements in the document and does not reject event-handler attributes or javascript: URLs on other elements. A crafted AMP email can execute arbitrary JavaScript when a recipient opens the message and enables the AMP toggle. The script can read the message DOM, exfiltrate message data, and display phishing overlays within the message-body area. Exploitation requires the recipient to enable the AMP toggle, and practical exposure is reduced because AMP email is uncommon. This issue is fixed in version 1.2319.",
  "id": "CVE-2026-54521",
  "modified": "2026-09-20T11:30:22.697302390Z",
  "published": "2026-09-17T20:17:47.341Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/M66B/FairEmail/releases/tag/1.2319"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54521.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/M66B/FairEmail/security/advisories/GHSA-r8ff-qr7g-pvw6"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-54521"
    },
    {
      "type": "FIX",
      "url": "https://github.com/M66B/FairEmail/commit/fb37bbfabf5e75d08f0cfa6ce9b84469d62a20a0"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "FairEmail: Cross-site scripting (XSS) in AMP message rendering (ActivityAMP)"
}