TREK MCP trip summary bypasses delegated OAuth read scopes (CVE-2026-77321) | HOL Guard CVE

Medium · CVSS 4.3CVE-2026-77321

TREK MCP trip summary bypasses delegated OAuth read scopes

Answer in brief

CVE-2026-77321 records a Medium severity (CVSS 4.3) vulnerability in TREK MCP trip summary bypasses delegated OAuth read scopes. The current sources do not mark it as known exploited. The current feed maps mauriceboe/TREK (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 24, 2026Updated Sep 24, 2026Source checked Sep 25, 2026First seen by HOL Sep 25, 2026Material review Sep 24, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 4.3
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 4.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps mauriceboe/TREK (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
mauriceboe/TREKgeneric	<3.3.0	3.3.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for mauriceboe/TREK.
Review the reported fix. Update mauriceboe/TREK to 3.3.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 25, 2026

Sources and claim methodology

Upstream source description

TREK is a collaborative travel planner. Prior to 3.3.0, the get_trip_summary tool in server/src/mcp/tools/trips.ts is registered for scoped OAuth MCP tokens without requiring trips:read and returns core trip summary data regardless of the delegated scopes. A token granted only an unrelated capability, such as weather:read, can receive trip metadata, member email addresses from server/src/services/tripService.ts, itinerary days, and accommodations for every trip accessible to the token's user. Cross-user trip authorization remains enforced, but the missing scope check defeats the consented least-privilege boundary and exposes trip content and third-party contact information to an MCP client that was not authorized to read it. This issue is fixed in version 3.3.0.

Quoted source text, attributed separately from HOL analysis.