{"id":"CVE-2021-21337","aliases":["GHSA-p44j-xrqg-4xrr","PYSEC-2021-45"],"title":"URL Redirection to Untrusted Site ('Open Redirect') in Products.PluggableAuthService","summary":"URL Redirection to Untrusted Site ('Open Redirect') in Products.PluggableAuthService","severity":"medium","cvss":5.7,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","vendor":"products-pluggableauthservice","product":"products-pluggableauthservice","ecosystem":"pip","affected":["products-pluggableauthservice < 2.6.1"],"patched":["products-pluggableauthservice 2.6.1"],"published":"2021-03-08","updated":"2026-07-08","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/GHSA-p44j-xrqg-4xrr","references":[{"url":"https://github.com/zopefoundation/Products.PluggableAuthService/security/advisories/GHSA-p44j-xrqg-4xrr"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-21337"},{"url":"https://github.com/zopefoundation/Products.PluggableAuthService/commit/7eead067898852ebd3e0f143bc51295928528dfa"},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/products-pluggableauthservice/PYSEC-2021-45.yaml"},{"url":"https://github.com/zopefoundation/Products.PluggableAuthService"},{"url":"https://pypi.org/project/Products.PluggableAuthService"},{"url":"http://packetstormsecurity.com/files/162911/Products.PluggableAuthService-2.6.0-Open-Redirect.html"}],"tags":["osv","pip","exploit-available"],"epss":0.08443,"epssPercentile":0.94804,"exploitAvailable":true,"ingestedAt":"2026-07-08T18:25:51.508Z","exploits":{"exploitdb":true,"checkedAt":"2026-09-25T08:20:37.917Z"},"slug":"CVE-2021-21337","body":"## Overview\n\n### Impact\n_What kind of vulnerability is it? Who is impacted?_\n\nOpen redirect vulnerability - a maliciously crafted link to the login form and login functionality could redirect the browser to a different website.\n\n### Patches\n_Has the problem been patched? What versions should users upgrade to?_\n\nThe 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\"`\n\n### Workarounds\n_Is there a way for users to fix or remediate the vulnerability without upgrading?_\n\nThere is no workaround. Users are encouraged to upgrade.\n\n### References\n_Are there any links users can visit to find out more?_\n\n- [GHSA-p44j-xrqg-4xrr](https://github.com/zopefoundation/Products.PluggableAuthService/security/advisories/GHSA-p44j-xrqg-4xrr)\n- [Products.PluggableAuthService on PyPI](https://pypi.org/project/Products.PluggableAuthService/)\n- [OWASP page on open redirects](https://cheatsheetseries.owasp.org/cheatsheets/Unvalidated_Redirects_and_Forwards_Cheat_Sheet.html)\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in the [Products.PluggableAuthService issue tracker](https://github.com/zopefoundation/Products.PluggableAuthService/issues)\n* Email us at [security@plone.org](mailto:security@plone.org)\n\n## Affected packages\n\n- `products-pluggableauthservice < 2.6.1`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `products-pluggableauthservice 2.6.1`","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":31.4,"likelihood":1.7,"exploitation":12,"ransomware":0},"changes":[]}