What’s Vulnerable › Vulnerabilities

CVE-2026-77321: TREK MCP trip summary bypasses delegated OAuth read scopes

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-24 · updated 2026-10-05
• Weakness: CWE-200

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.

Affected products

• mauriceboe TREK: before 3.3.0

References

• https://github.com/liketrek/TREK/commit/19064b39176660f3be3a2df198c87949504046e2
• https://github.com/liketrek/TREK/pull/1520
• https://github.com/liketrek/TREK/releases/tag/v3.3.0
• https://github.com/liketrek/TREK/security/advisories/GHSA-qvw8-w937-vcmq

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