Reference page — cumulative record through Saturday, October 3, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-91998

CVE-2026-91998CRITICAL

Casdoor through 4.4.0 Cross-Organization User Administration via /api/mcp

  AV  AC  AT  PR  UI  VC  VI  VA   CVSS    EPSS   %ile   KEV
   N   L   N   L   N   H   H   H    9.4   .0059   46.4     —

AFFECTED
  Product  Versions     Fixed
  casdoor  unspecified  —

TIMELINE
  Sep 15  Reserved by VulnCheck
  Sep 15  Published (CNA: VulnCheck)
  Sep 17  EXPLOIT PUBLISHED — CVE-2026-91998 (casdoor). Public exploit reference added.
  Sep 24  EXPLOIT PUBLISHED — CVE-2026-91998 (casdoor). Public exploit reference added.

CWE-863 · CNA: VulnCheck · CVSS v4.0 · 6 references · NVD status: Deferred

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.

Lifecycle

Complete event history — 4 events, chronological
Date	Event	Detail
September 15, 2026	Reserved	Reserved by VulnCheck
September 15, 2026	Published	Published (CNA: VulnCheck)
September 17, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-91998 (casdoor). Public exploit reference added.
September 24, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-91998 (casdoor). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
casdoor	casdoor	—	—	—

Weaknesses

CWE-863

References (6)

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

Authoritative record: CVE-2026-91998 at cve.org

Vendors: casdoor

Weaknesses: CWE-863

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-91998 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Saturday, October 3, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.