CVE-2021-20222: A flaw was found in keycloak

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HIGH 7.5WATCHLISTUPGRADE

CVE-2021-20222 is a high-severity flaw (CVSS 7.5) affecting keycloak. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A flaw was found in keycloak. The new account console in keycloak can allow malicious code to be executed using the referrer URL. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Why this priority

High severity
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.2% (top 32%)
CISA exploited list	No
Weakness	CWE-20, CWE-79
Published	2021-03-23
Last modified	2026-06-17

Publisher (CNA): Red Hat, Inc. · Vendor: redhat

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-03-23 17:15 UTCPublished CVE record published
2026-06-17 03:33 UTCUpdated Record last modified

redhat keycloak UPGRADE

Affected: >= 9.0.0 and < 13.0.0

Fixed in: 13.0.0

Safe to downgrade to: a release before 9.0.0

1. Check installed version

apt-cache policy keycloak || rpm -q keycloak || keycloak --version

2. UPGRADE to 13.0.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade keycloak

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade keycloak

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 9.0.0 (Debian / Ubuntu)

apt-cache madison keycloak sudo apt install keycloak=<VERSION_BEFORE_9.0.0> sudo apt-mark hold keycloak

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list keycloak sudo dnf downgrade keycloak-<VERSION_BEFORE_9.0.0> sudo dnf versionlock add keycloak

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-20222?

keycloak: upgrade to 13.0.0. Exact commands for each OS are on this page.

Is CVE-2021-20222 being exploited?

CVE-2021-20222 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-20222 affect?

CVE-2021-20222 affects keycloak. Severity is high (CVSS 7.5). A flaw was found in keycloak. The new account console in keycloak can allow malicious code to be executed using the referrer URL. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availabi

How urgent is CVE-2021-20222?

Priority 48/100. High severity; On your watchlist

Software pages

Keycloak vulnerabilities

Related CVEs

CVE-2023-6927 MEDIUM 4.6 MITIGATE DOWNGRADE A flaw was found in Keycloak
CVE-2023-6563 HIGH 7.7 UPGRADE DOWNGRADE An unconstrained memory consumption vulnerability was discovered in Keycloak
CVE-2023-6291 HIGH 7.1 UPGRADE DOWNGRADE A flaw was found in the redirect_uri validation logic in Keycloak
CVE-2023-6134 MEDIUM 4.6 UPGRADE UPGRADE A flaw was found in Keycloak that prevents certain schemes in redirects, but permits them if a wildcard is app
CVE-2025-8419 MEDIUM 5.3 MITIGATE A vulnerability was found in Keycloak-services

References

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