CVE-2021-20222Network attack vector

Reflected XSS via unescaped account-console referrer URL

Published Mar 23, 2021 · Updated Aug 3, 2024

Reflected XSS in the new account console in Red Hat build of Keycloak 13.0.0 allows remote attackers to execute script via a referrer URL. The keycloak.v2 account theme inserts referrer_uri into a JavaScript string with FreeMarker escaping disabled, allowing URL quotes to become executable script. The preview console must be enabled, and a user must follow the crafted flow and authenticate; execution occurs in that user's browser session.

CVSS severity7.5
High
EPSS probability1.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Reflected XSS in the new account console in Red Hat build of Keycloak 13.0.0 allows remote attackers to execute script via a referrer URL. The keycloak.v2 account theme inserts referrer_uri into a JavaScript string with FreeMarker escaping disabled, allowing URL quotes to become executable script. The preview console must be enabled, and a user must follow the crafted flow and authenticate; execution occurs in that user's browser session.

The record

CVE
CVE-2021-20222
Published
Mar 23, 2021
Updated
Aug 3, 2024
Vendor
Red Hat
Product
Red Hat build of Keycloak
Classifications
CWE-20, CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 23, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=keycloak 13.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Red Hat · Red Hat build of Keycloakversion=keycloak 13.0.0

Published CVSS scores

8.3GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
5.1NIST National Vulnerability DatabaseAV:N/AC:H/Au:N/C:P/I:P/A:P
7.5NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo