---
title: "CVE-2026-9098: Casdoor SAML callback handler accepts any well-formed SAMLResponse sent to /api/acs without verifying that it corresponds to an AuthnRequest"
url: https://erroneo.us/security/cve/CVE-2026-9098/
description: "CVE-2026-9098 (github.com/casdoor/casdoor (Go)): In Casdoor versions 2.362.0 and earlier, the SAML callback handler in controllers/auth.go accepts any…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-05-28
date_modified: 2026-07-02
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-9098"
kev: false
cvss: 9.1
epss: 0.00211
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-9098: Casdoor SAML callback handler accepts any well-formed SAMLResponse sent to /api/acs without verifying that it corresponds to an AuthnRequest

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.2% , percentile 11: FIRST’s model estimates a 0.2% chance of exploitation activity in the next 30 days, higher than 11% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes github.com/casdoor/casdoor (Go) <= 1.1000.1-0.20260321120606-239e8bd69487, no fixed version listed . Check your lockfile, including transitive dependencies.

## What it is

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.

## Affected packages

- Go `github.com/casdoor/casdoor` <= 1.1000.1-0.20260321120606-239e8bd69487 → fixed: none listed

## Affected products (CVE record)

- Casdoor Casdoor: <= 2.362.0

## Severity

- CISA-ADP CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`
- GitHub CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.21% probability of exploitation activity in the next 30 days; percentile 11.

## Sources

- [GitHub Advisory GHSA-mfvp-7p3v-x9mh](https://github.com/advisories/GHSA-mfvp-7p3v-x9mh)
- [CVE.org record CVE-2026-9098](https://www.cve.org/CVERecord?id=CVE-2026-9098)
- [NVD entry CVE-2026-9098](https://nvd.nist.gov/vuln/detail/CVE-2026-9098)
- [kb.cert.org](https://kb.cert.org/vuls/id/780781)

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Source page: https://erroneo.us/security/cve/CVE-2026-9098/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt