GHSA-jm8c-9f3j-4378

Suggest an improvement
Source
https://github.com/advisories/GHSA-jm8c-9f3j-4378
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-jm8c-9f3j-4378/GHSA-jm8c-9f3j-4378.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-jm8c-9f3j-4378
Aliases
Published
2026-04-18T01:11:19Z
Modified
2026-05-20T08:11:22.640173056Z
Severity
  • 6.1 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N CVSS Calculator
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.

The 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.

Credits

Thanks go to Mark Fijneman for finding and reporting a subset of this issue, which alerted us to the wider vulnerability.

Database specific 
{
    "cwe_ids": [
        "CWE-116",
        "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-18T01:11:19Z",
    "nvd_published_at": "2026-04-24T20:16:27Z",
    "severity": "MODERATE"
}
References

Affected packages

PyPI / pretalx

Package

Name
pretalx
View open source insights on deps.dev
Purl
pkg:pypi/pretalx

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2026.1.0

Affected versions

0.*
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.*
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.*
2.0.0
2.1.0
2.1.1
2.2.0
2.3.0
2.3.1
2.3.2
2023.*
2023.1.0
2023.1.1
2023.1.2
2023.1.3
2024.*
2024.1.0
2024.2.0
2024.2.1
2024.3.0
2024.3.1
2025.*
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"