Functype: MCP set_functype_version Package Alias RCE via Unsanitized pnpm install + Dynamic Import

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-59176
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-28 14:17:04 UTC
Updated2026-10-28 15:24:56 UTC
DescriptionFunctype is a family of TypeScript functional programming libraries. Prior to 1.4.4, the `set_functype_version` MCP tool in `functype-mcp-server` accepts an unconstrained `version` string using only `z.string()` validation in `packages/mcp-server/src/index.ts` and interpolates it into `functype@<version>` for `pnpm add`. Package-alias syntaxes such as `file:`, `npm:`, URLs, or paths can cause an arbitrary local or remote package to be installed as functype. Immediately afterward, `initDocsData(true)` in `packages/mcp-server/src/lib/docs/data.ts` resolves `functype/cli` and dynamically imports the newly installed module, executing attacker-controlled JavaScript with the MCP server process's privileges. Any MCP client able to send a `tools/call` request invoking the tool can exploit the flaw; the tool is enabled by default without authentication in `stdio` mode. A connected AI assistant susceptible to indirect prompt injection can also be induced to invoke it from a malicious document or web page. In non-default `TRANSPORT_TYPE=httpStream` deployments, a network-accessible attacker does not require local access. Successful execution can read process secrets, modify files, or terminate the server. This issue is fixed in `version` 1.4.4.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from [email protected]

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Problem Types: CWE-829 | CWE-829 CWE-829: Inclusion of Functionality from Untrusted Control Sphere

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Jordanburke Functype affected < 1.4.4 Not specified

References

ReferenceSourceLinkTags
github.com/jordanburke/functype/security/advisories/GHSA-wcjj-9m6g-2fr2 [email protected] github.com
github.com/jordanburke/functype/commit/c0d58ad9c2a7d15c6117bd3adbbd75de3... [email protected] github.com
github.com/jordanburke/functype/releases/tag/v1.4.4 [email protected] github.com
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