CVE-2026-91998 json
Casdoor through 4.4.0 Cross-Organization User Administration via /api/mcp
published 2026-09-15 54 d ago modified 2026-09-24 45 d ago also EUVD-2026-78438
- cvss
- 9.9
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.6%
- EPSS 0.6% chance of exploitation in 30 days, percentile 48%
- public exploits
- 0
- none known
Summary
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.
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- total
- Assessed
- 52 d ago
Exploit prediction
0.59% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/geo-chen/oss/blob/main/casdoor.md#finding-2-application-credential-authorization-bypass-in-apimcp-enables-unrestricted-cross-organization-user-administration referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 9.4 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H |
| CNA | 3.1 | 9.9 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
| CNA | 4.0 | 9.4 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected products
- casdoor casdoor
Classification
- Weakness
-
- CWE-863 Incorrect Authorization
References
-
github.com
/geo-chen/oss/blob/main/casdoor.md#finding-2-application-credential-authorization-bypass-in-apimcp-enables-unr
third-party-advisory, exploit
-
github.com
/casdoor/casdoor/blob/v4.4.0/authz/authz.go#L174-L176
technical-description
-
github.com
/casdoor/casdoor/blob/v4.4.0/routers/base.go#L122-L154
technical-description
-
github.com
/casdoor/casdoor/blob/v4.4.0/mcpself/user.go
technical-description
-
github.com
/casdoor/casdoor
product
-
vulncheck.com
/advisories/casdoor-through-4.4.0-cross-organization-user-administration-via-api-mcp
third-party-advisory
Sources
- CVE List CVE-2026-91998
- NVD CVE-2026-91998
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.