8.8

CVE-2026-9704: redhat build_of_keycloak

CVSS: 8.8v3.1HighModified
AliasesCGA-46f4-mwrp-xmwfCGA-6qcw-5vj7-v45fCGA-7r82-22hj-rgp2
Published 27-05-2026Last modified 26-06-2026
Open JSON

Vulnerability summary

CVE-2026-9704 is a high (CVSS 8.8) vulnerability in redhat build_of_keycloak. EPSS estimates a 0.59% chance of exploitation in the next 30 days, higher than 46.9% of scored vulnerabilities.

Overall risk
35/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.8/10
010
High · v3.1 (NVD)
EPSS score
0.59%
0%100%
Low · +0.27 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 27-05-2026
    PublishedVulnerability first disclosed.
  2. 26-06-2026
    Last modifiedVulnerability information updated.

Description

A flaw was found in Keycloak. An authenticated user with low privileges can exploit this vulnerability by sending an oversized subject_token JSON Web Token (JWT) to the TokenEndpoint. When the token exceeds a 4000-character limit, it is silently dropped, causing the system to fall back to client credentials. This allows the user to gain the permissions of the client's service account, leading to privilege escalation.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.59%

Chance of exploitation in the next 30 days

Percentile

47%

Versus all other CVEs

30-day change

+0.27 pp

From 0.32% on 18-09-2026

18-09-202618-10-2026
EPSS score
0.59%

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.keycloak2 products
  • keycloak-server-spi-private< 26.6.3
  • keycloak-services< 26.6.3
Redhat1 product

4 vendors · 19 products

References

11 links
Show all 11 references