VulnerabilityAwaiting classification

CVE-2026-9098

CRITICAL · 9.1 CVSS v3.1 Published 2026-05-28
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In Casdoor versions 2.362.0 and earlier, the SAML callback handler in controllers/auth.go accepts any well-formed SAMLResponse sent to /api/acs without verifying that it corresponds to an AuthnRequest previously issued by Casdoor. Additionally, if an administrator disables or deletes an IdP (Identity Provider) after a SAML flow has started, the handler still processes the response using the provider snapshot loaded at the start of the request. As a result, an attacker controlling a registered upstream IdP can send unsolicited SAML responses, or replay a legitimately captured response in a different session or after the original flow has ended. In both cases, Casdoor accepts the response and issues a session, enabling persistent unauthorized access.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Casdoor's SAML callback handler at /api/acs accepts any valid SAMLResponse without validating the InResponseTo attribute against a previously issued AuthnRequest, and continues processing using a stale IdP snapshot even after the IdP is disabled/deleted, allowing attackers to inject unsolicited or replayed SAML responses to hijack sessions.

MitigationImplement AuthnRequest tracking and InResponseTo validation to ensure responses are bound to legitimate requests, and add runtime IdP state verification before processing SAML responses.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if SAML IdP is configured
    Navigate to Casdoor's admin console and inspect the authentication methods. Look for any SAML Identity Provider (IdP) configurations under the authentication providers section.
    Affected if A SAML IdP is configured and enabled in Casdoor.
  2. Verify Casdoor version
    Check the installed Casdoor version by examining the binary or container image tag, or by querying the /api/version endpoint if available.
    Affected if The installed version is any version of Casdoor that supports SAML (the vulnerability exists in the SAML callback handler).
  3. Confirm /api/acs endpoint exists
    Verify the /api/acs endpoint is reachable in the Casdoor deployment by accessing it directly or reviewing the application's routing configuration.
    Affected if The /api/acs endpoint is present and exposed.
  4. Check IdP state persistence
    Review Casdoor's database or configuration storage to determine whether disabled or deleted IdP configurations are retained as snapshots that could be used for stale processing.
    Affected if IdP configurations remain in the system after being disabled or deleted.

A Casdoor instance is affected if it has SAML IdP authentication enabled and the /api/acs endpoint is accessible, regardless of IdP status, because the InResponseTo validation is missing and stale IdP snapshots are processed.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement AuthnRequest tracking and InResponseTo validation to ensure responses are bound to legitimate requests, and add runtime IdP state verification before processing SAML responses.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,600
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-9098 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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