How severe is CVE-2021-20195?

CVE-2021-20195 has a CVSS 3.x base score of 9.6, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-20195 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20195?

CVE-2021-20195 affects Redhat Keycloak. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-20195?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-20195 published?

CVE-2021-20195 was published on 2021-05-28 and last updated on 2026-06-17.

CVE-2021-20195

CVE-2021-20195 is a critical-severity vulnerability in Redhat Keycloak with a CVSS 3.x base score of 9.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-116.

Key facts

Severity: Critical (CVSS 3.x base score 9.6)
CVSS v2: 6.8
EPSS exploit prediction: 1% (66th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-116
Affected product: Redhat Keycloak
Published: 2021-05-28
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-20195?: 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.
How severe is CVE-2021-20195?: CVE-2021-20195 has a CVSS 3.x base score of 9.6, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-20195 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20195?: CVE-2021-20195 affects Redhat Keycloak. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-20195?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-20195 published?: CVE-2021-20195 was published on 2021-05-28 and last updated on 2026-06-17.

References

https://bugzilla.redhat.com/show_bug.cgi?id=1919143

Affected products (1)

cpe:2.3:a:redhat:keycloak:*:*:*:*:*:*:*:*

More vulnerabilities in Redhat Keycloak

CVE-2022-4361 — Critical (CVSS 10.0): Keycloak, an open-source identity and access management solution, has a cross-site scripting (XSS) vulnerability in the…
CVE-2022-1245 — Critical (CVSS 9.8): A privilege escalation flaw was found in the token exchange feature of keycloak. Missing authorization allows a client…
CVE-2019-14910 — Critical (CVSS 9.8): A vulnerability was found in keycloak 7.x, when keycloak is configured with LDAP user federation and StartTLS is used…
CVE-2022-3782 — Critical (CVSS 9.1): keycloak: path traversal via double URL encoding. A flaw was found in Keycloak, where it does not properly validate…
CVE-2019-14837 — Critical (CVSS 9.1): A flaw was found in keycloack before version 8.0.0. The owner of 'placeholder.org' domain can setup mail server on this…
CVE-2026-3047 — High (CVSS 8.8): A flaw was found in org.keycloak.broker.saml. When a disabled Security Assertion Markup Language (SAML) client is…

All CVEs affecting Redhat Keycloak →

Other CWE-116 vulnerabilities

CVE-2025-55730 — Critical (CVSS 10.0): XWiki Remote Macros provides XWiki rendering macros that are useful when migrating content from Confluence. Starting in…
CVE-2025-55729 — Critical (CVSS 10.0): XWiki Remote Macros provides XWiki rendering macros that are useful when migrating content from Confluence. Starting in…
CVE-2023-47143 — Critical (CVSS 10.0): IBM Tivoli Application Dependency Discovery Manager 7.3.0.0 through 7.3.0.10 is vulnerable to HTTP header injection,…
CVE-2023-26472 — Critical (CVSS 9.9): XWiki Platform is a generic wiki platform. Starting in version 6.2-milestone-1, one can execute any wiki content with…
CVE-2022-41934 — Critical (CVSS 9.9): XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. Any user with…
CVE-2022-36100 — Critical (CVSS 9.9): XWiki Platform Applications Tag and XWiki Platform Tag UI are tag applications for XWiki, a generic wiki platform.…

Browse all CWE-116 vulnerabilities →