CVE-2021-21291
4.7 · MEDIUMOverview
CVE-2021-21291 is a medium-severity vulnerability affecting oauth2_proxy_project oauth2_proxy. It was published on February 2, 2021 and has a CVSS 3.1 base score of 4.7 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 4.7, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
OAuth2 Proxy is an open-source reverse proxy and static file server that provides authentication using Providers (Google, GitHub, and others) to validate accounts by email, domain or group. In OAuth2 Proxy before version 7.0.0, for users that use the whitelist domain feature, a domain that ended in a similar way to the intended domain could have been allowed as a redirect. For example, if a whitelist domain was configured for ".example.com", the intention is that subdomains of example.com are allowed. Instead, "example.com" and "badexample.com" could also match. This is fixed in version 7.0.0 onwards. As a workaround, one can disable the whitelist domain feature and run separate OAuth2 Proxy instances for each subdomain.
Remediation
Check the references section for vendor advisories and patches from oauth2_proxy_project. Update oauth2_proxy to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| oauth2_proxy_project | oauth2_proxy | >= 0, < 7.0.0 | Affected |
References
Frequently Asked Questions
What is CVE-2021-21291?
CVE-2021-21291 is a medium-severity vulnerability affecting oauth2_proxy_project oauth2_proxy. It was published on February 2, 2021 and has a CVSS 3.1 base score of 4.7 (MEDIUM).
How severe is CVE-2021-21291?
This vulnerability has a CVSS 3.1 base score of 4.7, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2021-21291?
Check the references section for vendor advisories and patches from oauth2_proxy_project. Update oauth2_proxy to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-21291?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-21291 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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