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CVE-2021-32786

4.7 · MEDIUM

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.

Published Jul 22, 2021CWE-601EPSS 2.36%

Overview

CVE-2021-32786 is a medium-severity vulnerability. It was published on July 22, 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

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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. 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.

References

Refdaniel.haxx.se/blog/2017/01/30/one-url-standard-please/GitHubgithub.com/zmartzone/mod_auth_openidc/commit/3a115484eb927bc6daa5737dd84f88ff4bbc5544GitHubgithub.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9GitHubgithub.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-xm4c-5wm5-jqv7Reflists.debian.org/debian-lts-announce/2023/04/msg00034.htmlReflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FZVF6BSJLRQZ7PFFR4X5JSU6KUJYNOCU/Reflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QXAWKPT5LXZSUTFSJ6IWSZC7RMYYQXQD/Refsecurity.netapp.com/advisory/ntap-20210902-0001/Refwww.oracle.com/security-alerts/cpuapr2022.htmlRefdaniel.haxx.se/blog/2017/01/30/one-url-standard-please/

How CyberStrike helps

Frequently asked questions

What is CVE-2021-32786?

CVE-2021-32786 is a medium-severity vulnerability. It was published on July 22, 2021 and has a CVSS 3.1 base score of 4.7 (MEDIUM).

How severe is CVE-2021-32786?

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-2021-32786?

Check the references section for vendor advisories, patches, and mitigation guidance. 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-2021-32786?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-32786 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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