CVE-2023-6134

A flaw was found in Keycloak that prevents certain schemes in redirects, but permits them if a wildcard is appended to the token. This issue could allow an attacker to submit a specially crafted request leading to cross-site scripting (XSS) or further attacks. This flaw is the result of an incomplete fix for CVE-2020-10748.

What this means for your business

It affects Redhat Single Sign-On. It matters if your company, or a supplier that handles your data, runs it.
Code showing how to exploit it has been published, but real attacks have not been confirmed.
An attacker can use it remotely, over a network, with an ordinary user login, but only after tricking someone into an action such as opening a file or a link.
FIRST's prediction model gives it a 1% chance of attack attempts being seen in the next 30 days, ranking above 69% of all known flaws.

What to do

1Check whether your company or your suppliers run Redhat Single Sign-On, and which version. The affected versions are listed further down this page.
2If you do, apply the vendor's fix. A patch or vendor advisory has been published.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

Check if you’re exposed Book a call

Scoring

CVSS: 4.6 (v3.1)
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
Weakness: CWE-79
Assigned by: secalert@redhat.com

Dates

Published: 2023-12-14
Last modified: 2026-09-22
Sources: NVD

Affected products

Redhat Single Sign-On- 7.6, all versions
Redhat Enterprise Linux7.0, 8.0, 9.0
Redhat Keycloak- 22.0.7
Redhat Openshift Container Platform4.11, 4.12
Redhat Openshift Container Platform For Power4.9, 4.10
Redhat Openshift Container Platform Ibm Z Systems4.9, 4.10

As listed in the NVD configuration data. Not a statement about your estate.