CVE-2021-20195 keycloak Self Stored Cross-site Scripting vulnerability

What is CVE-2021-20195?

CVE-2021-20195 is a critical cross-site scripting vulnerability in Redhat Keycloak, published on 28 May 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

A flaw was found in keycloak in versions before 13.0.0. A Self Stored XSS attack vector escalating to a complete account takeover is possible due to user-supplied data fields not being properly encoded and Javascript code being used to process the data. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Weakness: CWE-116, CWE-20

Which versions are affected by CVE-2021-20195?

2 open source packages ship an affected version, including org.keycloak:keycloak-core. It affects 1 product.

Products include Redhat Keycloak.

How do I fix CVE-2021-20195?

Upgrade org.keycloak:keycloak-core to 13.0.0 or later.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2021-20195 being exploited?

There is no known exploitation of CVE-2021-20195 in the wild and no public exploit code.

Other vulnerabilities in Redhat Keycloak

• CVE-2022-4361 Keycloak vulnerable to cross-site scripting when validating URI-schemes on SAML and OIDC Critical 10.0
• CVE-2022-1245 Keycloak vulnerable to privilege escalation on Token Exchange feature Critical 9.8
• CVE-2019-14910 Keycloak Authentication Error Critical 9.3
• CVE-2019-14909 Keycloak Authentication Error Critical 9.3
• CVE-2022-3782 Keycloak vulnerable to path traversal via double URL encoding Critical 9.1

All Redhat Keycloak vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-q6w2-89hq-hq27.