Security audit
Security checks for vulnerabilities and agentic risk
The skill is a mostly coherent Cal.com integration, but it grants write access to bookings and availability schedules without enough built-in confirmation or scoping guidance.
Review this before installing if your Cal.com account is business-critical. Use a least-privilege API key, keep the key private, and require the agent to show booking or schedule details and get explicit approval before creating, cancelling, or replacing availability data.
The skill exposes a parameterized destructive endpoint, DELETE /bookings/{uid}, without documenting validation, ownership checks, or mandatory confirmation. In an agent/tooling context, an attacker could coerce cancellation of arbitrary bookings reachable by UID or exploit ambiguous input to trigger unauthorized destructive actions.
Endpoint: DELETE /bookings/{uid}
Headers:
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
6. **Create / Update Availability Schedule** — Define or modify weekly availability rules (working hours, date overrides).
7. **Get User Info** — Retrieve the authenticated user's profile, timezone, and default settings.
All API calls target `https://api.cal.com/v1`. Authentication uses a Bearer token (API key).
---
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
6. **Create / Update Availability Schedule** — Define or modify weekly availability rules (working hours, date overrides).
7. **Get User Info** — Retrieve the authenticated user's profile, timezone, and default settings.
All API calls target `https://api.cal.com/v1`. Authentication uses a Bearer token (API key).
---
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
6. **Create / Update Availability Schedule** — Define or modify weekly availability rules (working hours, date overrides).
7. **Get User Info** — Retrieve the authenticated user's profile, timezone, and default settings.
All API calls target `https://api.cal.com/v1`. Authentication uses a Bearer token (API key).
---
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
6. **Create / Update Availability Schedule** — Define or modify weekly availability rules (working hours, date overrides).
7. **Get User Info** — Retrieve the authenticated user's profile, timezone, and default settings.
All API calls target `https://api.cal.com/v1`. Authentication uses a Bearer token (API key).
---
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
6. **Create / Update Availability Schedule** — Define or modify weekly availability rules (working hours, date overrides).
7. **Get User Info** — Retrieve the authenticated user's profile, timezone, and default settings.
All API calls target `https://api.cal.com/v1`. Authentication uses a Bearer token (API key).
---
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
6. **Create / Update Availability Schedule** — Define or modify weekly availability rules (working hours, date overrides).
7. **Get User Info** — Retrieve the authenticated user's profile, timezone, and default settings.
All API calls target `https://api.cal.com/v1`. Authentication uses a Bearer token (API key).
---
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
6. **Create / Update Availability Schedule** — Define or modify weekly availability rules (working hours, date overrides).
7. **Get User Info** — Retrieve the authenticated user's profile, timezone, and default settings.
All API calls target `https://api.cal.com/v1`. Authentication uses a Bearer token (API key).
---
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
6. **Create / Update Availability Schedule** — Define or modify weekly availability rules (working hours, date overrides).
7. **Get User Info** — Retrieve the authenticated user's profile, timezone, and default settings.
All API calls target `https://api.cal.com/v1`. Authentication uses a Bearer token (API key).
---
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
6. **Create / Update Availability Schedule** — Define or modify weekly availability rules (working hours, date overrides).
7. **Get User Info** — Retrieve the authenticated user's profile, timezone, and default settings.
All API calls target `https://api.cal.com/v1`. Authentication uses a Bearer token (API key).
---
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
6. **Create / Update Availability Schedule** — Define or modify weekly availability rules (working hours, date overrides).
7. **Get User Info** — Retrieve the authenticated user's profile, timezone, and default settings.
All API calls target `https://api.cal.com/v1`. Authentication uses a Bearer token (API key).
---
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
6. **Create / Update Availability Schedule** — Define or modify weekly availability rules (working hours, date overrides).
7. **Get User Info** — Retrieve the authenticated user's profile, timezone, and default settings.
All API calls target `https://api.cal.com/v1`. Authentication uses a Bearer token (API key).
---
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
6. **Create / Update Availability Schedule** — Define or modify weekly availability rules (working hours, date overrides).
7. **Get User Info** — Retrieve the authenticated user's profile, timezone, and default settings.
All API calls target `https://api.cal.com/v1`. Authentication uses a Bearer token (API key).
---
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
Example cURL:
curl -s "https://api.cal.com/v1/event-types" \
-H "Authorization: Bearer ${CAL_COM_API_KEY}"
The booking flow sends attendee name, email, timezone, and notes to an external service without documenting a privacy notice or consent step. In agent environments, transmitting third-party personal data without a warning can lead to unintended disclosure and privacy/compliance issues.
Multiple examples hard-code Asia/Shanghai and present user-facing output in Shanghai time as the default, which can amount to an implicit locale/timezone constraint without opt-in. The policy requires offering language or locale choice unless the locale restriction is clearly justified.
The cancellation flow performs a destructive DELETE action with no documented confirmation, preview, or warning requirement. In an agent setting, ambiguous user input or prompt manipulation could cause unintended booking cancellations, impacting availability and business operations.
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
Example cURL:
curl -s "https://api.cal.com/v1/slots?eventTypeId=evt_abc123&startTime=2026-07-10T00:00:00Z&endTime=2026-07-15T23:59:59Z" \
-H "Authorization: Bearer ${CAL_COM_API_KEY}"
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
Creating a booking for July 10, 2026 at 14:00 Shanghai time (UTC+8).
curl -s -X POST "https://api.cal.com/v1/bookings" \
-H "Authorization: Bearer ${CAL_COM_API_KEY}" \
-H "Content-Type: application/json" \
-d '{
The 'Output Format' section states that the skill 'Always returns' a normalized JSON wrapper with fields like status, action, and data/error. However, the rest of the file is purely operational documentation for direct Cal.com API calls, with examples showing raw API responses and shell commands, and no code or mechanism that would actually guarantee this wrapper format.
The example lists UTC timestamps such as 2026-07-13T02:00:00Z and summarizes them as 10:00 AM Shanghai time, which requires adding 8 hours, not subtracting 8 hours. The parenthetical note therefore actively contradicts the example's own interpreted output and could mislead downstream implementations or users.
No suspicious patterns detected.