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Fencer Vulns
medium 4.8

CVE-2020-10776 json

Cross-site Scripting in keycloak

published 2020-11-17 5 y ago modified 2026-06-17 4 mo ago also GHSA-484q-784p-8m5h , EUVD-2022-0807

cvss
4.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 56%
public exploits
0
none known

Summary

A flaw was found in Keycloak before version 12.0.0, where it is possible to add unsafe schemes for the redirect_uri parameter. This flaw allows an attacker to perform a Cross-site scripting attack.

Patch / fix

  • maven org.keycloak:keycloak-server-spi-private 12.0.0
  • maven org.keycloak:keycloak-services 12.0.0
  • redhat keycloak 12.0.0
  • rh-sso7-keycloak red hat single sign on 7 9.0.9-1.redhat_00001.1.el8sso
  • rh-sso7-keycloak-server red hat single sign on 7 9.0.9-1.redhat_00001.1.el8sso
  • rh-sso7-libunix-dbus-java red hat single sign on 7 0.8.0-2.el8sso
  • rh-sso7-keycloak red hat single sign on 7 9.0.9-1.redhat_00001.1.el7sso
  • rh-sso7-keycloak-server red hat single sign on 7 9.0.9-1.redhat_00001.1.el7sso
  • rh-sso7-keycloak red hat single sign on 7 9.0.9-1.redhat_00001.1.el6sso
  • rh-sso7-keycloak-server red hat single sign on 7 9.0.9-1.redhat_00001.1.el6sso

red hat advisories RHSA-2020:4932RHSA-2020:4930RHSA-2020:4929

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-10776 updated cvss 4.0

keycloak: OIDC redirect_uri allows dangerous schemes resulting in potential XSS

  • Red Hat Single Sign-On 7.4 for RHEL 6 Server rh-sso7-keycloak 9.0.9-1.redhat_00001.1.el6sso, rh-sso7-keycloak-server 9.0.9-1.redhat_00001.1.el6sso
    fixed: vendor fix “Trusted Hosts Policy could be used to mitigate this attack : https://www.keycloak.org/docs/latest/securing_apps/index.html#client-registration-policies” RHSA-2020:4929
  • Red Hat Single Sign-On 7.4 for RHEL 7 Server rh-sso7-keycloak 9.0.9-1.redhat_00001.1.el7sso, rh-sso7-keycloak-server 9.0.9-1.redhat_00001.1.el7sso
    fixed: vendor fix “Trusted Hosts Policy could be used to mitigate this attack : https://www.keycloak.org/docs/latest/securing_apps/index.html#client-registration-policies” RHSA-2020:4930
  • Red Hat Single Sign-On 7.4 for RHEL 8 rh-sso7-libunix-dbus-java 0.8.0-2.el8sso, rh-sso7-keycloak 9.0.9-1.redhat_00001.1.el8sso, rh-sso7-keycloak-server 9.0.9-1.redhat_00001.1.el8sso
    fixed: vendor fix “Trusted Hosts Policy could be used to mitigate this attack : https://www.keycloak.org/docs/latest/securing_apps/index.html#client-registration-policies” RHSA-2020:4932
  • Red Hat Single Sign-On 7.4.3
    fixed: vendor fix “Trusted Hosts Policy could be used to mitigate this attack : https://www.keycloak.org/docs/latest/securing_apps/index.html#client-registration-policies” RHSA-2020:4931
  • Red Hat Decision Manager 7 keycloak keycloak Red Hat Fuse 7 keycloak keycloak Red Hat OpenShift Application Runtimes keycloak keycloak Red Hat Process Automation 7 keycloak keycloak Red Hat support for Spring Boot keycloak keycloak
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.78% chance of exploitation in the next 30 days, higher than 56% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 4.8 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 3.5 AV:N/AC:M/Au:S/C:N/I:P/A:N
GitHub 3.1 4.8 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
maven org.keycloak:keycloak-server-spi-private
<12.0.0
12.0.0
maven org.keycloak:keycloak-services
<12.0.0
12.0.0

Affected products

  • n/a keycloak

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.