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PatchSiren cyber security CVE debrief

CVE-2026-7307 Red Hat CVE debrief

A flaw in Keycloak allows a remote, unauthenticated attacker to send specially crafted XML input to the SAML endpoint, causing high CPU usage and worker thread starvation, leading to a Denial of Service (DoS). This issue affects Keycloak servers with SAML endpoints exposed to untrusted networks. Defenders should assess their exposure and apply necessary patches or mitigations to prevent potential DoS attacks. The vulnerability is tracked as CVE-2026-7307 and has a CVSS score of 7.5, indicating a high severity level.

Vendor
Red Hat
Product
Red Hat build of Keycloak 26.2
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-19
Original CVE updated
2026-10-06
Advisory published
2026-05-19
Advisory updated
2026-10-06

Who should care

Defenders responsible for Keycloak servers, especially those with SAML endpoints exposed to untrusted networks, should assess their exposure and apply necessary patches or mitigations.

Why it matters

CVE-2026-7307 is a Denial of Service (DoS) vulnerability in Keycloak's SAML endpoint. Defenders should verify exposure, apply patches, and monitor server performance to prevent potential DoS attacks.

  • Potential Denial of Service (DoS) attacks on Keycloak servers
  • Increased CPU usage and worker thread starvation
  • Service unavailability due to DoS attacks

Technical summary

The vulnerability exists in the SAML endpoint of Keycloak, allowing a remote attacker to send specially crafted XML input, leading to high CPU usage and worker thread starvation, resulting in a Denial of Service (DoS). This issue affects Keycloak servers with SAML endpoints exposed to untrusted networks. The vulnerability has a CVSS score of 7.5, indicating a high severity level. Defenders should prioritize verifying exposure of Keycloak servers and apply vendor-provided patches or mitigations to prevent potential DoS attacks.

Defensive priority

Defenders should prioritize verifying exposure of Keycloak servers, especially those with SAML endpoints exposed to untrusted networks, and apply vendor-provided patches or mitigations.

Recommended defensive actions

  • Verify exposure of Keycloak servers with SAML endpoints exposed to untrusted networks
  • Apply vendor-provided patches or mitigations
  • Monitor Keycloak server performance for signs of DoS attacks
  • Restrict access to SAML endpoints to trusted networks only
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its description, CVSS score, and affected products. Vendor advisories from Red Hat offer guidance on mitigation and patches.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-7307 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-7307

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-7307 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-7307

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.