Sources: National Vulnerability Database, CVE.org, CISA KEV, FIRST EPSS
CVE-2026-107123 Overview
A flaw was found in the SAML XML processing component of Keycloak, an open-source identity and access management solution. The issue occurs when the server parses XML documents containing excessively long dateTime or duration values. Because these strings are not properly validated before processing, the XML parser consumes excessive CPU time. An unauthenticated remote attacker can exploit this by sending specially crafted SAML requests to the server, leading to high CPU utilization and a denial of service for all users.
Critical Impact
Affected Products
- SAML XML processing component of Keycloak: see the vendor advisory for the exact affected versions
Discovery Timeline
- 2026-11-05: CVE-2026-107123 published to the National Vulnerability Database by secalert@redhat.com
- 2026-11-05: last updated in the NVD database
Technical Details for CVE-2026-107123
Vulnerability Analysis
CVE-2026-107123 is a Uncontrolled Resource Consumption weakness (CWE-400: Uncontrolled Resource Consumption) in SAML XML processing component of Keycloak. Based on its CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction. An attacker can exhaust CPU, memory or connections.
With a CVSS base score of 7.5, apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Root Cause
The weakness is classified as CWE-400: Uncontrolled Resource Consumption. An attacker can exhaust CPU, memory or connections.
Attack Vector
Based on the CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction. Attack complexity is low complexity.
No exploitation in the wild is confirmed by CISA at the time of the last update. Check the references below for any vendor or researcher proof of concept.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Detection Methods for CVE-2026-107123
Detection Strategies
- Inventory every instance of SAML XML processing component of Keycloak and compare the running version with the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Run an authenticated vulnerability scan once your scanner ships a check for this CVE.
Monitoring Recommendations
- Forward SAML XML processing component of Keycloak application, access and audit logs to your SIEM for retrospective hunting.
- Alert on new processes, configuration changes or outbound connections from the affected service.
- Track the vendor advisory and the CISA KEV catalog for changes in exploitation status.
How to Mitigate CVE-2026-107123
Immediate Actions Required
- Apply the fixed version of SAML XML processing component of Keycloak named in the vendor advisory.
- Prioritize internet facing and business critical instances first.
- Rescan after the change to confirm the exposure is closed.
Patch Information
Use the fixed version listed in the vendor advisory for SAML XML processing component of Keycloak.
Workarounds
- If patching must wait, restrict network access to the affected service and place it behind authentication or a web application firewall rule.
CWE References
- CWE-400: Uncontrolled Resource Consumption More CVEs with this weakness
Technical References
This entry is built directly from NVD, CISA KEV and EPSS data. Verify fixed versions in the vendor advisory before you deploy.
Frequently asked questions
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