# CVE-2026-9090: CVE-2026-9090

> Attackers can bypass SAML authentication in Casdoor by forging assertions with arbitrary certificates, leading to unauthorized access.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 May 2026
- **Updated:** 29 May 2026
- **Also known as:** GHSA-fwgq-j9r9-qjgr, GO-2026-5895

## What is CVE-2026-9090?

CVE-2026-9090 is a critical authentication bypass vulnerability in Casdoor, published on 28 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Casdoor versions 2.362.0 and earlier contain a vulnerability that allows an attacker to bypass authentication by supplying an arbitrary signing certificate. The buildSpCertificateStore function extracts the X.509 certificate directly from the incoming SAMLResponse instead of using the trusted pre-configured Identity Provider certificate, allowing an attacker to forge assertions signed with an attacker-controlled key.

## Which versions are affected by CVE-2026-9090?

3 open source packages ship an affected version, including github.com/casdoor/casdoor.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/casdoor/casdoor` | Go | All versions | None |
| `github.com/casdoor/casdoor` | Go | All versions to 1.1000.1-0.20260321120606-239e8bd69487 | None |
| `github.com/casdoor/casdoor` | Go | All versions to 1.1000.1-0.20260321120606-239e8bd69487 | None |

## How do I fix CVE-2026-9090?

Upgrade to a fixed version.

## Is CVE-2026-9090 being exploited?

There is no known exploitation of CVE-2026-9090 in the wild and no public exploit code.

Public exploit code:

- https://github.com/George0Papasotiriou/CVE-2026-9090-Modbus-TCP-Write-to-Read-Only-Coils-via-Function-Code-Spoofing (github_poc): https://github.com/George0Papasotiriou/CVE-2026-9090-Modbus-TCP-Write-to-Read-Only-Coils-via-Function-Code-Spoofing
- PoC for CVE-2026-9090 — Casdoor SAML signature bypass (CWE-347). Reproduction-only; coordinated via CERT/CC VU#780781. (github_poc): https://github.com/Kimdir01/CVE-2026-9090-poc

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-9090 and fix it if it is affected.

What it is: CVE-2026-9090 is a critical authentication bypass vulnerability in Casdoor, published on 28 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-9090 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/casdoor/casdoor (Go): affected all versions; no fix listed
- github.com/casdoor/casdoor (Go): affected all versions up to 1.1000.1-0.20260321120606-239e8bd69487; no fix listed
- github.com/casdoor/casdoor (Go): affected all versions up to 1.1000.1-0.20260321120606-239e8bd69487; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-9090/ (Markdown: https://insights.sbomify.com/CVE-2026-9090/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-9090
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-9090
- OSV: https://osv.dev/vulnerability/CVE-2026-9090

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-9090/
Summaries are generated and may contain mistakes; the official description above is the record.