server-sequential-thinking
npm:@modelcontextprotocol/server-sequential-thinking@2025.12.18
github.com/modelcontextprotocol/servers
Severity breakdown
Worst finding
Tool `sequentialthinking` accepts unconstrained string input
· sequentialthinking
The following string parameter(s) have no `maxLength` constraint: `branchId`, `thought`. Unbounded strings let an attacker stuff arbitrary payloads through the tool, including indirect-injection content.
fix: Add a `maxLength` to each string property, or constrain with an `enum` or `pattern`. Most legitimate tool inputs fit under a few hundred bytes.
All 1 finding
- mediumTool `sequentialthinking` accepts unconstrained string input· sequentialthinkingunconstrained input
The following string parameter(s) have no `maxLength` constraint: `branchId`, `thought`. Unbounded strings let an attacker stuff arbitrary payloads through the tool, including indirect-injection content.
fix: Add a `maxLength` to each string property, or constrain with an `enum` or `pattern`. Most legitimate tool inputs fit under a few hundred bytes.
How this was scored
Source sandbox — live tools/list captured in an ephemeral Docker container (parameter schemas included → R1/R2/R4 fire). Findings are emitted by the public capframe.findings.v1 schema. Score = 100 − (10·Critical + 4·High + 2·Medium + 1·Low), clamped to [0, 100].
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