CVE-2026-91998

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.59% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 48.1% of scored records. A rank, not a probability.

NVD base score

9.4 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Deferred. NVD last modified this record on 2026-09-23.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-09-15 11:35Z1 MO AGO

Last updated

2026-09-24 14:22Z1 MO AGO

Reserved

2026-09-15

Assigning CNA

VulnCheck

Record state

PUBLISHED

Severity

Critical (CVSS 9.4)

CNA CVSS vector

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

Weaknesses

• CWE-863Incorrect AuthorizationClass

Data version

5.2

Document digest

52a5b771c2fa0001ff2c8e613dd20ccae1193e438a10d4fed7d74637a6ee2c78

• github.comResearcher write-up, Finding 2https://github.com/geo-chen/oss/blob/main/casdoor.md#finding-2-application-credential-authorization-bypass-in-apimcp-enables-unrestricted-cross-organization-user-administrationthird-party-advisoryexploit
• github.comauthz/authz.go unconditional app allow at v4.4.0https://github.com/casdoor/casdoor/blob/v4.4.0/authz/authz.go#L174-L176technical-description
• github.comgetUsernameByClientIdSecret at v4.4.0https://github.com/casdoor/casdoor/blob/v4.4.0/routers/base.go#L122-L154technical-description
• github.commcpself/user.go unscoped user tools at v4.4.0https://github.com/casdoor/casdoor/blob/v4.4.0/mcpself/user.gotechnical-description
• github.comhttps://github.com/casdoor/casdoorproduct
• www.vulncheck.comVulnCheck Advisory: Casdoor through 4.4.0 Cross-Organization User Administration via /api/mcphttps://www.vulncheck.com/advisories/casdoor-through-4.4.0-cross-organization-user-administration-via-api-mcpthird-party-advisory