CVE-2020-27838

mediumpriority · track · 42EPSS 0.179 · 97 %ileexploit · PoCEUUS

grimoire priorityP1 · Urgent

Exploitable?

Public exploit

1 exploit · PoC

Likely / severe?

17.9% (97th) EPSS

CVSS 4.3 · medium

Is it mine?

4 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · osv

EPSS · scored 2026-10-27

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.

cvss

Technical severity, 0–10. One row per scoring source.

6.5

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.04.3mediumAV:N/AC:M/Au:N/C:P/I:N/A:Nprimary · NVD / NIST USexploitability 8.6 · impact 2.9

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:Nprimary · NVD / NIST USexploitability 2.8 · impact 3.6

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:Nsecondary · OSV

v3.16.4mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:Fsecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-287USCWE-287US

exploits (1)

Public proof-of-concept and weaponised exploit code.

Cappricio-Securities/CVE-2020-27838CVE-2020-27838 - KeyCloak - Information Exposure PoC · poc_in_github

affected products (4)

Products and version ranges known to be affected.

n/a KeyCloak≤ keycloak 13.0.0enisa_euvdEU
redhat keycloak< 13.0.0nvdUScpe:2.3:a:redhat:keycloak:*:*:*:*:*:*:*:*
redhat single sign-on= 7.0nvdUScpe:2.3:a:redhat:single_sign-on:*:*:*:*:*:*:*:*
Maven org.keycloak:keycloak-core< 13.0.0osvUSpkg:maven/org.keycloak/keycloak-core

advisories (1)

Vendor and ecosystem advisories describing this.

GHSA-pcv5-m2wh-66j3Keycloak discloses information without authentication2022-05-24ghsa · osvUS
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.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd osv NVD CVE.org MITRE

published 2021-03-08modified 2026-06-17

references (5)

External citations — patches, advisories, analysis.

scry

Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.

Free scan