CVE-2021-32786
CVSS v3
6.1
MEDIUM
EPSS Score
0.1 %
exploit probability
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In versions prior to 2.4.9, `oidc_validate_redirect_url()` does not parse URLs the same way as most browsers do. As a result, this function can be bypassed and leads to an Open Redirect vulnerability in the logout functionality. This bug has been fixed in version 2.4.9 by replacing any backslash of the URL to redirect with slashes to address a particular breaking change between the different specifications (RFC2396 / RFC3986 and WHATWG). As a workaround, this vulnerability can be mitigated by configuring `mod_auth_openidc` to only allow redirection whose destination matches a given regular expression.
Technical details
- Published
- 2021-07-22
Frequently asked questions
What is CVE-2021-32786?
mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In versions prior to 2.4.9, `oidc_validate_redirect_url()` does not parse URLs the same way as most browsers do. As a result, this function can be bypassed and leads to an Open Redirect vulnerability in the logout functionality. This bug has been fixed in version 2.4.9 by replacing any backslash of the URL to redirect with slashes to address a particular breaking change between the different specifications (RFC2396 / RFC3986 and WHATWG). As a workaround, this vulnerability can be mitigated by configuring `mod_auth_openidc` to only allow redirection whose destination matches a given regular expression.
Is CVE-2021-32786 actively exploited?
Active exploitation of CVE-2021-32786 has not been confirmed. The EPSS score is 0.1%, indicating the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-32786?
CVE-2021-32786 has a CVSS v3 base score of 6.1 (MEDIUM severity).
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