Bug 2001646 (CVE-2021-39191) - CVE-2021-39191 mod_auth_openidc: open redirect due to target_link_uri parameter not validated
Summary: CVE-2021-39191 mod_auth_openidc: open redirect due to target_link_uri paramet...
Alias: CVE-2021-39191
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 2001647 2001852 2001853
Blocks: 2001648
TreeView+ depends on / blocked
Reported: 2021-09-06 16:40 UTC by Guilherme de Almeida Suckevicz
Modified: 2022-05-17 09:58 UTC (History)
4 users (show)

Fixed In Version: mod_auth_openidc
Doc Type: If docs needed, set a value
Doc Text:
A open redirect flaw was found in mod_auth_openidc where it does not sanitize target_link_uri paramater properly. This issue could be used by a remote attacker to facilitate phishing attacks by tricking users into visiting a trusted web application URL that redirects to an external and potentially malicious server. As a result of this redirection victim users may give more credibility to the attacker controlled server because coming from a trusted application.
Clone Of:
Last Closed: 2022-05-11 03:16:55 UTC

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2022:1823 0 None None None 2022-05-10 13:40:05 UTC

Description Guilherme de Almeida Suckevicz 2021-09-06 16:40:11 UTC
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, 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 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.


Upstream patch:

Comment 1 Guilherme de Almeida Suckevicz 2021-09-06 16:40:24 UTC
Created mod_auth_openidc tracking bugs for this issue:

Affects: fedora-all [bug 2001647]

Comment 4 errata-xmlrpc 2022-05-10 13:40:03 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2022:1823 https://access.redhat.com/errata/RHSA-2022:1823

Comment 5 Product Security DevOps Team 2022-05-11 03:16:54 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):


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