CVE-2026-16100Network attack vectorHinoki check available

Authenticated service crash via unbounded metric cardinality

Published Aug 5, 2026 · Updated Aug 5, 2026

Resource exhaustion in Red Hat build of Keycloak 26.6 before 26.6.5 allows remote authenticated users to crash the server. User-event metrics copy raw request-controlled error text, including nonexistent client identifiers, into Prometheus label values without cardinality limits. Metrics must be enabled, and the attacker needs account-management permissions; repeated unique failures consume memory until the service crashes.

CVSS severity6.5
Medium
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Resource exhaustion in Red Hat build of Keycloak 26.6 before 26.6.5 allows remote authenticated users to crash the server. User-event metrics copy raw request-controlled error text, including nonexistent client identifiers, into Prometheus label values without cardinality limits. Metrics must be enabled, and the attacker needs account-management permissions; repeated unique failures consume memory until the service crashes.

The record

CVE
CVE-2026-16100
Published
Aug 5, 2026
Updated
Aug 5, 2026
Vendor
389 Directory Server
Product
Red Hat build of Keycloak
Classifications
CWE-770, T1499.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

389 Directory Server · Red Hat build of KeycloakAffected versions are unavailable in this record.

Published CVSS scores

6.5Red HatCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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