CVE-2026-91998 casdoor CVE debrief

Who should care

Defenders responsible for Casdoor instances, especially those using version 4.4.0 or earlier, should assess exposure and prioritize mitigation to prevent potential unauthorized access to user administration across all organizations.

Why it matters

Defenders should prioritize verifying and mitigating this vulnerability in Casdoor instances, especially those using version 4.4.0 or earlier, to prevent potential unauthorized access to user administration across all organizations.

• Potential unauthorized access to user administration across all organizations
• Enumeration of user records including password salts and email addresses
• Creation of administrator accounts
• Modification or deletion of existing users

Technical summary

The CVE record and NVD entry provide details on the authorization bypass vulnerability in Casdoor through 4.4.0, which allows attackers with any application's clientId and clientSecret to gain unrestricted access to user administration across all organizations. This vulnerability could lead to serious security breaches, including user enumeration, unauthorized account creation, and modification or deletion of existing users. The vulnerability is particularly concerning because it can be exploited using legitimate credentials from a single application, making it difficult to detect and prevent.

Defensive priority

Defenders should prioritize verifying and mitigating this vulnerability in Casdoor instances, especially those using version 4.4.0 or earlier, to prevent potential unauthorized access to user administration across all organizations.

Recommended defensive actions

• Verify and mitigate this vulnerability in Casdoor instances, especially those using version 4.4.0 or earlier.
• Restrict access to the /api/mcp endpoint to prevent unauthorized access to user administration.
• Monitor for potential exploitation attempts and update to a fixed version if available.
• 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.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE record and NVD entry provide details on the authorization bypass vulnerability in Casdoor through 4.4.0, which allows attackers with any application's clientId and clientSecret to gain unrestricted access to user administration across all organizations.

Sources and 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.