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Paperclip: Unauthenticated Access to Multiple API Endpoints in Authenticated Mode

High severity GitHub Reviewed Published Apr 16, 2026 in paperclipai/paperclip

Package

npm @paperclipai/server (npm)

Affected versions

< 2026.416.0

Patched versions

2026.416.0

Description

Summary

Several API endpoints in authenticated mode have no authentication at all. They respond to completely unauthenticated requests with sensitive data or allow state-changing operations. No account, no session, no API key needed.

Verified against the latest version.

Discord: sagi03581

Steps to Reproduce

1. Unauthenticated issue data access

GET /api/heartbeat-runs/:runId/issues returns issue data for a heartbeat run with zero authentication. Every other endpoint in server/src/routes/activity.ts calls assertCompanyAccess, but this one was missed.

curl -s http://<target>:3100/api/heartbeat-runs/00000000-0000-0000-0000-000000000001/issues
# -> []  (HTTP 200, not 401 or 403)

If an attacker obtains a valid run UUID (from logs, error messages, shared URLs, or by probing), they can read issue data without any credentials.

2. Unauthenticated CLI auth challenge creation

POST /api/cli-auth/challenges creates a CLI authentication challenge with no actor check at all. The handler at server/src/routes/access.ts:1638-1659 skips any auth verification.

curl -s -X POST -H "Content-Type: application/json" \
  -d '{"command":"test"}' \
  http://<target>:3100/api/cli-auth/challenges
# returns challenge ID, token, and a pre-generated board API key

The response includes a boardApiToken that becomes active once the challenge is approved. Combined with open registration (separate report), this enables persistent API key generation.

3. Unauthenticated agent instruction / system prompt leakage

These endpoints in server/src/routes/access.ts require no authentication:

curl -s http://<target>:3100/api/skills/index
# returns all available skill endpoints

curl -s http://<target>:3100/api/skills/paperclip
# returns the FULL agent heartbeat procedure including:
#   - every API endpoint and its parameters
#   - authentication mechanism (env var names, header formats)
#   - the complete agent coordination protocol
#   - the agent creation/hiring workflow

curl -s http://<target>:3100/api/skills/paperclip-create-agent
# returns the full agent creation workflow with adapter configs

This hands an attacker a complete map of the internal API without authenticating. It also leaks how agents authenticate, how heartbeats work, and what adapter configurations are available.

4. Unauthenticated deployment configuration disclosure

GET /api/health returns deployment mode, exposure setting, auth status, bootstrap status, version, and feature flags.

curl -s http://<target>:3100/api/health
# {
#   "deploymentMode": "authenticated",
#   "deploymentExposure": "public",
#   "authReady": true,
#   "bootstrapStatus": "ready",
#   "version": "2026.403.0",
#   ...
# }

Tells an attacker exactly how the instance is configured, whether registration is available, and what version is running.

Impact

  • Data exposure: heartbeat run issues accessible without credentials. Agent instructions and full API structure exposed to anyone.
  • Reconnaissance: an attacker can fingerprint the deployment (mode, version, features) and map the entire internal API before attempting anything else.
  • Auth bypass stepping stone: unauthenticated CLI challenge creation is a building block for the full RCE chain (reported separately).

Suggested Fixes

  1. Add authentication to heartbeat run issues in server/src/routes/activity.ts:

    • GET /api/heartbeat-runs/:runId/issues -- add assertCompanyAccess like every other endpoint in the same file
  2. Add authentication to CLI challenge creation in server/src/routes/access.ts:

    • POST /api/cli-auth/challenges -- add assertBoard at minimum
  3. Add authentication to skill endpoints in server/src/routes/access.ts:

    • GET /api/skills/available
    • GET /api/skills/index
    • GET /api/skills/:skillName
  4. Reduce health endpoint information -- consider removing deploymentMode, deploymentExposure, and version from the unauthenticated response, or gating the full response behind assertBoard

  5. Consider a global auth rejection middleware for all /api/* routes in authenticated mode. Currently unauthenticated requests get actor: { type: "none" } and pass through to next(), relying on each route handler to check individually. A missing check means an open endpoint. Rejecting type: "none" at the middleware level for all routes except an explicit public allowlist (health, sign-in, sign-up, webhooks) would prevent this class of bug entirely.

Contact

Discord: sagi03581

Happy to help verify fixes or provide additional details.

References

@cryppadotta cryppadotta published to paperclipai/paperclip Apr 16, 2026
Published to the GitHub Advisory Database Apr 16, 2026
Reviewed Apr 16, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L

EPSS score

Weaknesses

Missing Authentication for Critical Function

The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. Learn more on MITRE.

CVE ID

No known CVE

GHSA ID

GHSA-xfqj-r5qw-8g4j

Source code

Credits

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