What’s Vulnerable › Vulnerabilities

CVE-2026-91998: Casdoor through 4.4.0 Cross-Organization User Administration via /api/mcp

• Severity: critical (CVSS 9.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-15 · updated 2026-09-23
• Weakness: CWE-863

Description

Casdoor through 4.4.0 contains an authorization bypass vulnerability in the /api/mcp endpoint that allows attackers with any application's clientId and clientSecret to gain unrestricted access to user administration across all organizations. Attackers can enumerate user records including password salts and email addresses, create administrator accounts, modify existing users, and delete them in any organization by supplying legitimate credentials from a single application.

Affected products

• Casdoor: through 4.4.0

References

• https://github.com/casdoor/casdoor
• https://github.com/casdoor/casdoor/blob/v4.4.0/authz/authz.go#L174-L176
• https://github.com/casdoor/casdoor/blob/v4.4.0/mcpself/user.go
• https://github.com/casdoor/casdoor/blob/v4.4.0/routers/base.go#L122-L154
• https://github.com/geo-chen/oss/blob/main/casdoor.md#finding-2-application-credential-authorization-bypass-in-apimcp-enables-unrestricted-cross-organization-user-administration
• https://www.vulncheck.com/advisories/casdoor-through-4.4.0-cross-organization-user-administration-via-api-mcp

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