CVE-2021-39191 URL Redirection to Untrusted Site ('Open Redirect') in mod_auth_openidc
Attackers can redirect users to malicious sites via crafted URLs in the mod_auth_openidc module, requiring an upgrade to patched versions.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2021-39191?
CVE-2021-39191 is a medium-severity vulnerability in Debian Debian Linux, published on 3 Sep 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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 2.4.9.4, the 3rd-party init SSO functionality of mod_auth_openidc was reported to be vulnerable to an open redirect attack by supplying a crafted URL in the `target_link_uri` parameter. A patch in version 2.4.9.4 made it so that the `OIDCRedirectURLsAllowed` setting must be applied to the `target_link_uri` parameter. There are no known workarounds aside from upgrading to a patched version.
Weakness: CWE-601
Which versions are affected by CVE-2021-39191?
It affects 3 products.
Products include Debian Debian Linux, Fedoraproject Fedora, Openidc Mod Auth Openidc.
How do I fix CVE-2021-39191?
Upgrade to a fixed version.
Is CVE-2021-39191 being exploited?
There is no known exploitation of CVE-2021-39191 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-7289, DEBIAN-CVE-2021-39191, GHSA-2pgf-8h6h-gqg2, UBUNTU-CVE-2021-39191.