{"id":"GHSA-jm8c-9f3j-4378","summary":"pretalx mail templates vulnerable to email injection via unescaped user-controlled placeholders","details":"An unauthenticated attacker can send arbitrary HTML-rendered emails from a pretalx instance's configured sender address by embedding malformed HTML or markdown link syntax in a user-controlled template placeholder such as the account display name. The most direct vector is the password-reset flow: the attacker registers an account with a malicious name, enters the victim's email address, and triggers a password reset. The resulting email is delivered from the event's legitimate sender address and passes SPF/DKIM/DMARC validation, making it a ready-made phishing vector.\n\nThe same class of bug affects every mail template that interpolates a user-controlled placeholder (speaker name, proposal title, biography, question answers, etc.), including organiser-triggered emails such as acceptance/rejection notifications.\n\n### Credits\n\nThanks go to Mark Fijneman for finding and reporting a subset of this issue, which alerted us to the wider vulnerability.","aliases":["CVE-2026-41426","PYSEC-2026-109"],"modified":"2026-06-08T19:15:13.810245726Z","published":"2026-04-18T01:11:19Z","database_specific":{"github_reviewed_at":"2026-04-18T01:11:19Z","nvd_published_at":"2026-04-24T20:16:27Z","cwe_ids":["CWE-116","CWE-79"],"severity":"MODERATE","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/pretalx/pretalx/security/advisories/GHSA-jm8c-9f3j-4378"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-41426"},{"type":"PACKAGE","url":"https://github.com/pretalx/pretalx"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/pretalx/PYSEC-2026-109.yaml"}],"affected":[{"package":{"name":"pretalx","ecosystem":"PyPI","purl":"pkg:pypi/pretalx"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2026.1.0"}]}],"versions":["0.1.0","0.2.0.post1","0.2.1.post1","0.2.2","0.3.0","0.3.1","0.4.0","0.4.1","0.5.0","0.6.0","0.6.1","0.7.0","0.7.1","0.8.0","0.9.0","1.0.0","1.0.1","1.0.2","1.0.3","1.0.4","1.1.0","1.1.1","1.1.2","2.0.0","2.1.0","2.1.1","2.2.0","2.3.0","2.3.1","2.3.2","2023.1.0","2023.1.1","2023.1.2","2023.1.3","2024.1.0","2024.2.0","2024.2.1","2024.3.0","2024.3.1","2025.1.0","2025.2.0","2025.2.1","2025.2.2"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-jm8c-9f3j-4378/GHSA-jm8c-9f3j-4378.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"}]}