8.1

CVE-2026-9087: redhat build_of_keycloak

CVSS: 8.1v3.1HighModified
AliasesCGA-2mr4-5wvh-jhv4CGA-945f-g88f-f4qfCGA-9pmq-2q89-c83m
Published 20-05-2026Last modified 03-08-2026
Open JSON

Vulnerability summary

CVE-2026-9087 is a high (CVSS 8.1) vulnerability in redhat build_of_keycloak. EPSS estimates a 0.39% chance of exploitation in the next 30 days, higher than 32% of scored vulnerabilities.

Overall risk
32/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.1/10
010
High · v3.1 (NVD)
EPSS score
0.39%
0%100%
Low · +0.08 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 20-05-2026
    PublishedVulnerability first disclosed.
  2. 03-08-2026
    Last modifiedVulnerability information updated.

Description

A flaw was found in Keycloak. The cross-session verification proof is keyed only by (local userId, idpAlias) and is not bound to the upstream identity that was actually verified, so a second upstream account on the same IdP can consume it and get linked to the victim's local account.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.39%

Chance of exploitation in the next 30 days

Percentile

32%

Versus all other CVEs

30-day change

+0.08 pp

From 0.31% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.39%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard12 products
  • keycloak-26.4All versions (No fix recorded)
  • keycloak-26.4-iamguarded-compatAll versions (No fix recorded)
  • keycloak-26.5All versions (No fix recorded)
  • keycloak-26.5-iamguarded-compatAll versions (No fix recorded)
  • keycloak-fips-26.4All versions (No fix recorded)
Wolfi4 products
  • keycloak-26.4All versions (No fix recorded)
  • keycloak-26.4-iamguarded-compatAll versions (No fix recorded)
  • keycloak-26.5All versions (No fix recorded)
  • keycloak-26.5-iamguarded-compatAll versions (No fix recorded)
Org.keycloak1 product
  • keycloak-services< 26.6.3
Redhat1 product

4 vendors · 18 products

References

10 links