CVE-2020-11053: oauth2_proxy_project oauth2_proxy Open Redirect

Vulnerability summary

CVE-2020-11053 is a high (CVSS 7.1) Open Redirect vulnerability in oauth2_proxy_project oauth2_proxy. EPSS estimates a 0.79% chance of exploitation in the next 30 days, higher than 55.7% of scored vulnerabilities.

Timeline

1. 07-05-2020
   PublishedVulnerability first disclosed.
2. 04-08-2024
   Last modifiedVulnerability information updated.

Description

In OAuth2 Proxy before 5.1.1, there is an open redirect vulnerability. Users can provide a redirect address for the proxy to send the authenticated user to at the end of the authentication flow. This is expected to be the original URL that the user was trying to access. This redirect URL is checked within the proxy and validated before redirecting the user to prevent malicious actors providing redirects to potentially harmful sites. However, by crafting a redirect URL with HTML encoded whitespace characters the validation could be bypassed and allow a redirect to any URL provided. This has been patched in 5.1.1.

• CWE-601URL Redirection to Untrusted Site ('Open Redirect')The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.