Hub/AI Security/Advisories/GHSA-x863-g495-4cjc
Missing user ID claims collapse authenticated principals and allow MCP session hijacking
MCP C# SDK security advisory.
| GHSA | GHSA-x863-g495-4cjc |
|---|---|
| Published | Nov 3, 2026 |
| Severity | High 7.5 |
| CVE | None assigned |
| Status | patched |
| Affected | >= 0.1.0-preview.9, < 1.4.2, >= 2.0.0-preview.1, < 2.3.1 |
| Fixed in | 1.4.2, 2.3.1 |
| Component | MCP C# SDK |
Sources
Checked 2026-11-04. We copy severity and fix versions from the source and never estimate them.
Affected tools
Weekly, free
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