VulnTideExploited vulnerabilities, by vendor. Data as of .
Not in CISA KEVPublished CVSS 5.4 mediumEPSS 0.4% probability of exploitation in 30 daysFound by AI: OpenAI
Red Hat

CVE-2026-16093: Keycloak-services: keycloak-services: required signed-jwt assertion policy can be bypassed with unsigned assertion headers

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of . If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?
0.4%

EPSS score, percentile 33.4 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?
5.4 Medium

CVSS v3.1 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (2)

Which versions are affected?

Unaffected 26.6.7-3; 26.6-20; 26.6-20

Versions by product

Source: CISA KEV 2026.10.29, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.

What to do

Advisories and patches

This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

Red Hat Red Hat build of Keycloak 26.6
StatusVersions
Unaffected26.6.7-3

Versions not listed are: affected.

Red Hat Red Hat build of Keycloak 26.6
StatusVersions
Unaffected26.6-20

Versions not listed are: affected.

Red Hat Red Hat build of Keycloak 26.6
StatusVersions
Unaffected26.6-20

Versions not listed are: affected.

Red Hat Red Hat build of Keycloak 26.6.7
StatusVersions

Versions not listed are: unaffected.

Red Hat Red Hat build of Keycloak 26.6.7
StatusVersions

Versions not listed are: unaffected.

Red Hat Red Hat build of Keycloak 26.6.7
StatusVersions

Versions not listed are: unaffected.

Red Hat Red Hat Data Grid 8
StatusVersions

Versions not listed are: affected.

Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack
StatusVersions

Versions not listed are: affected.

Red Hat Red Hat Single Sign-On 7
StatusVersions

Versions not listed are: affected.

Versions the record lists as unaffected: 26.6.7-3, 26.6-20.

Source: CVE List, as of . About the data.

About this vulnerability

Keycloak provides a mechanism called Client Policies to enforce security requirements on clients, such as requiring them to use signed JWTs for authentication. A flaw was discovered where this enforcement can be bypassed. An attacker with valid client credentials can provide a fake, unsigned assertion header that tricks the system into thinking the policy requirements have been met. This allows t…

Summary: CVE record, as of .

  • CISA has not added CVE-2026-16093 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
  • The CVE record was published on 17 Jul 2026.
  • The CVE record carries a CVSS v3.1 base score of 5.4 (Medium), given by its CNA.
  • FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.4% (percentile 33.4), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
  • CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact partial.
  • The credits in the CVE record name OpenAI as finder.

Source: CISA KEV 2026.10.29, as of ; CVE List, as of ; FIRST EPSS, as of . About the data.

Description

Keycloak-services: keycloak-services: required signed-jwt assertion policy can be bypassed with unsigned assertion headers

Keycloak provides a mechanism called Client Policies to enforce security requirements on clients, such as requiring them to use signed JWTs for authentication. A flaw was discovered where this enforcement can be bypassed. An attacker with valid client credentials can provide a fake, unsigned assertion header that tricks the system into thinking the policy requirements have been met. This allows the attacker to authenticate using simpler methods like a client secret even when the administrator has mandated more secure, signed assertions.

Source: CVE List, as of . About the data.

Weakness

CWE-807

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.

Timeline

DateEvent
CVE record published
CVE record last updated

References

2

Known exploited Red Hat vulnerabilities

  • CVE-2015-3246: Red Hat Libuser Race Condition Vulnerability (added )
  • CVE-2015-5287: Red Hat Automatic Bug Reporting Tool Privilege Escalation Vulnerability (added )
  • CVE-2018-14667: Red Hat JBoss RichFaces Framework Expression Language Injection Vulnerability (added )
  • CVE-2021-3560: Red Hat Polkit Incorrect Authorization Vulnerability (added )
  • CVE-2021-4034: Red Hat Polkit Out-of-Bounds Read and Write Vulnerability (added )