Junglewise Threat Intelligence

CVE-2026-63765: Chatwoot authentication bypass in conversation direct uploads

CVE-2026-63765 · Severity: high · CVSS 8.2 · Published 2026-07-23

Executive brief

Chatwoot, an open-source customer engagement platform, contained a security flaw that allowed unauthorized individuals to upload files to any customer account without logging in. An attacker could exploit this to store arbitrary data on the company's servers, potentially leading to storage exhaustion or the hosting of malicious content. This issue has been resolved in version 4.16.0.

Technical details

An authentication bypass exists in the `Api::V1::Accounts::Conversations::DirectUploadsController` because it inherited directly from `ActiveStorage::DirectUploadsController` without implementing the standard API authentication stack. Additionally, the `EnsureCurrentAccountHelper#ensure_current_account` helper failed to enforce membership checks when `current_user` was nil, allowing unauthenticated requests to proceed. A remote, unauthenticated attacker can exploit this by sending a POST request to the conversation direct uploads endpoint to obtain signed PUT URLs. This allows the attacker to write arbitrary data to the application's storage backend (e.g., S3, GCS, or local disk) across different tenant accounts. The vulnerability is fixed in version 4.16.0 by aligning the controller with standard account authentication and updating the account helper to return a 401 status for unauthenticated requests.

Affected products

  • Chatwoot Chatwoot < 4.16.0

Timeline

  • 2026-06-13: disclosed: Initial report of the vulnerability
  • 2026-07-16: patched: Fix merged into develop branch via PR #15039
  • 2026-07-23: advisory: CVE-2026-63765 published

References

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