Keycloak-services: keycloak-services: unauthenticated cpu exhaustion via saml 1.1 keyinfo infinite loop
- Exploited
- No known exploitation
- Fix
- No fix listed
- Who is exposed
- Default setups
Do first: Check every install: default setups are affected.
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 45/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Default setups
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Keycloak, an open-source identity and access management server, can be made to hang by a flaw in its SAML 1.1 XML parsing. An unauthenticated attacker can reach it remotely by sending specially crafted requests, which drive CPU usage to 100% and cause a full denial of service that only a server restart clears.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
A flaw was found in the SAML 1.1 XML parsing logic of Keycloak, an open-source identity and access management solution. The issue occurs when the parser encounters unexpected elements within a security token's key information section, causing the processing thread to enter an infinite loop. An unauthenticated remote attacker could exploit this by sending specially crafted requests, leading to 100% CPU usage and a total denial of service that requires a server restart to resolve.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure22/25Default setups, reachable over the network without a login
- Reach10/20Shipped in major Linux distributions
- Severity7.5/10CVSS 7.5
- No patch5/5No patch listed yet
What would change the score
- Would score about 85 if added to CISA KEV
- Would score about 80 if CISA's SSVC rates exploitation active
What to do
Check every install: default setups are affected.
Workaround: The checked facts record no fix and no workaround. Check the Red Hat advisory for any mitigation published while the fix is pending.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- keycloak-services
Version range not reported
- rhbk/keycloak-rhel9
Version range not reported
- keycloak-services
Version range not reported
Evidence 2
- Report
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-107602
Is CVE-2026-107602 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
When Keycloak parses the ds:KeyInfo element in a SAML 1.1 assertion and meets a child element its parser does not handle, such as ds:KeyName, the parser can loop without end. The reported impact is CPU and worker-thread exhaustion that causes a full denial of service, which requires a server restart to clear.Source: bugzilla.redhat.com, access.redhat.com
Am I affected, and how do I check?
The checked facts list Red Hat Build of Keycloak and Red Hat Single Sign-On 7 as affected products, but no version ranges. The trigger is Keycloak processing SAML 1.1 assertions that contain unexpected elements in ds:KeyInfo. To check a deployment, confirm the installed product version and whether SAML 1.1 assertions are processed, then compare against the vendor advisory.Source: bugzilla.redhat.com, access.redhat.com
How do I fix CVE-2026-107602?
The checked facts do not name a fixed version, so the upgrade target cannot be confirmed from them. Use the Red Hat advisory for the fixed release of the installed product line.Source: bugzilla.redhat.com, access.redhat.com
What if there's no patch?
The checked facts record no fix and no workaround. Check the Red Hat advisory for any mitigation published while the fix is pending.Source: bugzilla.redhat.com, access.redhat.com