CVE-2026-16100
No exploitation reported by the sources we read.
- Published2026-08-05
- Fixed in26.6.5
- WeaknessCWE-770
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
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.
Timeline
dates in UTC- 2026-08-0515:16CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 21:37 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-16100?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-16100?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD · OSV| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 26.6 | ≥ 26.6, < 26.6.5 | 26.6.5 | NVD |
| 26.6 | ≥ 26.6.0, < 26.6.5 | 26.6.5 | OSV |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Distribution builds and vendor advisories
Packages from OSV.dev and products from the vendors' CSAF advisories.
version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.
Vendor advisories
keycloak-services: keycloak-services: Unbounded metric cardinality in user event metrics via request-controlled error text
Red Hat Security Advisory: Red Hat build of Keycloak 26.6.5 Images Security Update
Red Hat Security Advisory: Red Hat build of Keycloak 26.6.5 Security Update
Fix
- Update Redhat build of keycloak to 26.6.5
- Vendor fix Red Hat Product Security RHSA-2026:50849 · 9 productsBefore applying the update, back up your existing installation, including all applications, configuration files, databases and database settings, and so on.
- Workaround from the vendor Red Hat Product Security RHSA-2026:50849 · 9 productsMitigation 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
- access.redhat.comVendor Advisory
- access.redhat.comVendor Advisory
- access.redhat.comVendor Advisory
- bugzilla.redhat.comVendor Advisory
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Published
- 2026-08-05
- Last Modified
- 2026-08-31
- NVD status
- Modified
Frequently asked questions
What is CVE-2026-16100?
Is CVE-2026-16100 actively exploited?
What is the CVSS score for CVE-2026-16100?
Running keycloak? Hear about its next vulnerability
Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».
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Go further
- Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.