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CVE-2020-27838 keycloak

Affected softwarekeycloak
Severity6.5 Medium CVSS 3.1 2 scores
Fixed in13.0.0
WeaknessImproper authentication (CWE-287)
Published8 Mar 2021
Updated17 Jun 2026

Description

A flaw was found in keycloak in versions prior to 13.0.0. The client registration endpoint allows fetching information about PUBLIC clients (like client secret) without authentication which could be an issue if the same PUBLIC client changed to CONFIDENTIAL later. The highest threat from this vulnerability is to data confidentiality.

Exploitation status

Working exploit published

A reviewed exploit catalogue lists ready-to-run exploit code for this CVE.

  • CISA KEV not listed
  • VulnCheck KEV not listed
  • CISA Vulnrichment no assessment published
  • Indexed PoC 2 indexed Published artifacts you can open, in GitHub PoC, Nuclei; first seen 2024-05-14.
  • EPSS 18% chance in 30 days A model's forecast, not a report of exploitation. Higher than 97% of all scored CVEs.

1 of these are GitHub repositories with fewer than 5 stars. They are listed for reference and don't count toward the exploitation status above.

IndexArtifactStarsFirst seen
GitHub PoC CVE-2020-27838 - KeyCloak - Information Exposure 3 2024-05-14
Nuclei KeyCloak - Information Exposure

Waratek protection

Mitigation candidate

A kind of vulnerability Waratek's rules address, with exploit code published or exploitation reported. No rule exists and none is planned yet. The decision below says what we found to build a rule from.

  • Protection none
  • Action unverified
  • Review automated Inferred
  • Record active
Decided by A reference pointing at the upstream fix: a commit, a PR, a Red Hat bug
Finding A Red Hat Bugzilla ticket (https://bugzilla.redhat.com/show_bug.cgi?id=1906797) tracks the fix. That makes this CVE a candidate for an ARMR patch rule. No rule exists and none is scheduled: whether one can be derived depends on reading the upstream change the ticket links.
Candidate fix https://bugzilla.redhat.com/show_bug.cgi?id=1906797 : a Red Hat bug: the triage, which links onward to the fix

CVSS

6.5 MEDIUM v3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N 2 metrics

We show the highest score from the newest CVSS version. Scores from different versions can't be compared, and the first score listed is sometimes a 0.0 placeholder.

VersionScoreBandVectorAssignerType
CVSS 3.1 6.5 MEDIUM CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N NVD Primary published
CVSS 2.0 4.3 none AV:N/AC:M/Au:N/C:P/I:N/A:N NVD Primary

Affected software and releases

Maven packages

Affected and fixed versions, from OSV.dev
PackageIntroducedFixedLast affected
org.keycloak:keycloak-core 0 13.0.0 unbounded

Products and versions

3 products, 3 version entries
SourceVendorProductSchemeAffected versions
osv org.keycloak keycloak-core generic < 13.0.0
nvd redhat keycloak generic < 13.0.0
nvd redhat single sign-on generic 7.0

References

URLTags
https://bugzilla.redhat.com/show_bug.cgi?id=1906797 bugzilla
https://github.com/keycloak/keycloak/pull/7790 WEB
https://github.com/keycloak/keycloak/commit/9356843c6c3d7097d010b3bb6f91e25fcaba378c WEB

Timeline

Published2021-03-08By the CVE Program.
NVD record modified2026-06-17NVD's own last-modified date for this record.