Zuke: Command-form registry descriptors bypass the MCP launch policy
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-862.
Summary
Zuke, a code-first build automation system for Deno, has a missing authorization flaw (CWE-862) in the @zuke/core MCP registry mode before 1.51.0. Command-form registry descriptors skip the ZUKE_REGISTRY_LAUNCH_HOSTS check that applies to remote module descriptors. When zuke mcp runs with --registry and --allow-run against a registry that another party can write, that writer can choose the program and arguments a run-capable caller executes, with the operator's environment and workspace access.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
Description from the CNA
Zuke is a code-first, strongly typed build automation system for Deno. Prior to 1.51.0, the @zuke/core MCP registry mode accepts command-form registry descriptors without applying the ZUKE_REGISTRY_LAUNCH_HOSTS authorization enforced for remote module descriptors. When zuke mcp --registry --allow-run reads a registry writable by another party and a run-capable caller invokes the affected tool, the registry writer can choose the program and arguments executed with the operator's environment and workspace access. The --allow-run and --protect name globs do not contain the issue because the descriptor supplies those names, and the optional destructive confirmation displays a description controlled by the same writer. The local default registry populated only through zuke register is not affected because that command writes module-form descriptors. This issue is fixed in version 1.51.0.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| zuke-build | zuke | before 1.51.0 | 1.51.0 | Patch available | CNA |
- zuke Vendorzuke-build Affected before 1.51.0 Fixed in 1.51.0 Patch available CNA
Remediation
Upgrade Zuke to version 1.51.0, which fixes this issue. The affected product is zuke from zuke-build.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
- Fix · CNA zuke (zuke-build) Fixed in 1.51.0
Timeline
- 2026-10-30 Threatist record created from CVE-2026-119287
- 2026-11-01 Priority changed: MEDIUM → LOW
- 2026-11-04 CISA SSVC decision points changed
References
More zuke-build vulnerabilities
- TI-2026-83202 Zuke writes resolved secrets in cleartext to GitHub step summaries CVSS 3.1HIGH 7.5
- TI-2026-83199 Argument injection in Zuke on Windows via cmd.exe batch shims CVSS 3.1HIGH 7.0
- TI-2026-83201 Spoofable workflow run matching in Zuke githubWorkflow gate CVSS 3.1HIGH 7.1
- TI-2026-83203 Symlink following in zuke setup and import allows outside writes CVSS 3.1MEDIUM 5.5
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences