CVE-2021-21291
MEDIUM EPSS 68.1%
Published Feb 2, 20215y ago · Modified Jun 17, 20262w ago
6.1 CVSS 3.1
Published Feb 2, 2021 5y ago
Last Modified Jun 17, 2026 2w ago
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.
CVSS Details
Base Score
Exploitability
Impact
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction Required
Scope Changed
Confidentiality Low
Integrity Low
Availability None
Threat Intelligence
EPSS Exploit Probability
68.1% percentile
Exploit & Patch Status
Public Exploit Known
Patch Available
Weaknesses 1
CWE-601
Affected Products 1
| Vendor | Product | Version | Range |
|---|---|---|---|
| oauth2_proxy_project | oauth2_proxy | * | <7.0.0 |
References 4
- github.com https://github.com/oauth2-proxy/oauth2-proxy/commit/780ae4f3c99b579cb2ea9845121caebb6192f725
- github.com https://github.com/oauth2-proxy/oauth2-proxy/releases/tag/v7.0.0
- github.com https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-4mf2-f3wh-gvf2
- pkg.go.dev https://pkg.go.dev/github.com/oauth2-proxy/oauth2-proxy/v7
Remediation
- github.com https://github.com/oauth2-proxy/oauth2-proxy/commit/780ae4f3c99b579cb2ea9845121caebb6192f725