MCP Broken Token Validation (Accepts Forged Tokens)
mcp-broken-token-validation is a high severity check in the
ai category, written in python.
Its source is templates/ai/mcp/mcp-broken-token-validation.py in
cert-x-gen-templates.
What it checks
Section titled “What it checks”ACTIVE check. Detects MCP token-verification tools that accept forged, never-issued tokens (broken authentication)
Header
Section titled “Header”| Field | Value |
|---|---|
| Id | mcp-broken-token-validation |
| Severity | high |
| Language | python |
| Category | ai |
| Author | Bugb Research |
| Template version | 1.1.0 |
| Confidence | 80 |
| CVSS | 8.1 |
| Weakness | CWE-287 |
| Tags | mcp, ai, agent, broken-auth, token-validation, intrusive, active, cwe-287 |
| Target kind | not recorded |
| Oracle | not recorded |
References
Section titled “References”Declared in the header. cxg parses @references and then discards it, and
nothing at scan time reads it, so this is the only place the links a
template cites are surfaced.
Run it
Section titled “Run it”To see what the copy on your machine says about itself, and to confirm it is installed at all:
cxg template info mcp-broken-token-validationThe id it prints is the one to pass anywhere a template is selected. See
cxg template for the rest of
the subcommand, Scan a target for running
a scan, and
A match is not a finding for how
to read what comes back.
Related
Section titled “Related”- Template catalog is the whole corpus.
- ai is the rest of this category.
- Templates by weakness class groups checks by the defect they look for.
- Contribute a template is the route from a check you needed and could not find to a merged one.