VulnTideExploited vulnerabilities, by vendor. Data as of .
Not in CISA KEVPublished CVSS 6.5 mediumEPSS 0.6% probability of exploitation in 30 daysFound by AI: OpenAI
Red Hat

CVE-2026-16100: Keycloak-services: keycloak-services: unbounded metric cardinality in user event metrics via request-controlled error text

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?
0.6%

EPSS score, percentile 46 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?
6.5 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 26.6.5-1; 26.6-11; 26.6-11

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

Workaround (from the CVE record)

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

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
Unaffected26.6.5-1

Versions not listed are: affected.

Red Hat Red Hat build of Keycloak 26.6
StatusVersions
Unaffected26.6-11

Versions not listed are: affected.

Red Hat Red Hat build of Keycloak 26.6
StatusVersions
Unaffected26.6-11

Versions not listed are: affected.

Red Hat Red Hat build of Keycloak 26.6.5
StatusVersions

Versions not listed are: unaffected.

Red Hat Red Hat build of Keycloak 26.6.5
StatusVersions

Versions not listed are: unaffected.

Red Hat Red Hat build of Keycloak 26.6.5
StatusVersions

Versions not listed are: unaffected.

Red Hat Red Hat Data Grid 8
StatusVersions

Versions not listed are: unaffected.

Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack
StatusVersions

Versions not listed are: unaffected.

Red Hat Red Hat Single Sign-On 7
StatusVersions

Versions not listed are: unaffected.

Versions the record lists as unaffected: 26.6.5-1, 26.6-11.

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

About this vulnerability

A flaw was found in the user-event metrics recording of Keycloak. When metrics are enabled, the system records raw error messages from failed account operations as Prometheus metric labels. Because these error messages can include user-supplied input like nonexistent client IDs, an authenticated user can create a massive number of unique metric entries, eventually exhausting system memory and cau…

Summary: CVE record, as of .

  • CISA has not added CVE-2026-16100 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
  • The CVE record was published on 5 Aug 2026.
  • The CVE record carries a CVSS v3.1 base score of 6.5 (Medium), given by its CNA.
  • FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.6% (percentile 46), 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: unbounded metric cardinality in user event metrics via request-controlled error text

A flaw was found in the user-event metrics recording of Keycloak. When metrics are enabled, the system records raw error messages from failed account operations as Prometheus metric labels. Because these error messages can include user-supplied input like nonexistent client IDs, an authenticated user can create a massive number of unique metric entries, eventually exhausting system memory and causing the service to crash or become unavailable.

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

Weakness

CWE-770

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 )