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Fencer Intel
medium 6.4

CVE-2020-1727 json

A vulnerability was found in Keycloak before 9.0.2, where every Authorization URL that points to an IDP server lacks proper input validatio…

published 6y ago modified 4mo ago also EUVD-2020-12575

cvss
6.4
version 3.1, CNA
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 vulnerability was found in Keycloak before 9.0.2, where every Authorization URL that points to an IDP server lacks proper input validation as it allows a wide range of characters. This flaw allows a malicious to craft deep links that introduce further attack scenarios on affected clients.

Patch / fix

  • redhat keycloak 9.0.2

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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-2020-1727 updated cvss 6.4

keycloak: missing input validation in IDP authorization URLs

  • Red Hat Fuse 7 keycloak keycloak Red Hat OpenShift Application Runtimes keycloak keycloak Red Hat Single Sign-On 7 rh-sso7-keycloak rh-sso7-keycloak
    affected: no fix available
  • Red Hat Runtimes Spring Boot 2.2.6
    fixed: vendor fix RHSA-2020:2252
  • Red Hat Single Sign-On 7.4.0
    fixed: vendor fix RHSA-2020:5625
  • Red Hat Text-Only RHOAR
    fixed: vendor fix RHSA-2020:2905

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

0.80% chance of exploitation in the next 30 days, higher than 56% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 6.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
NVD 2.0 5.5 AV:N/AC:L/Au:S/C:P/I:P/A:N

Affected products

  • [UNKNOWN] keycloak

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Intel 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.