CVE-2026-41896
Coolify: Unauthenticated Deployment Trigger via Webhook HMAC Bypass with Null Secret
Description
Coolify is an open-source and self-hostable tool for managing servers, applications, and databases. Prior to 4.0.0-beta.474, the HMAC key is the application's manual_webhook_secret_github field, which is used by Coolify's webhook endpoints to validate incoming requests, is nullable with no default — meaning newly created applications have a null webhook secret. PHP's hash_hmac() function silently coerces a null key to an empty string ''. So when the secret is null, the server computes hash_hmac('sha256', $payload, '') — a deterministic value that any attacker can calculate independently. By sending X-Hub-Signature-256: sha256=<hash_hmac('sha256', payload, '')>, an unauthenticated attacker can forge a valid signature and trigger deployments. This vulnerability is fixed in 4.0.0-beta.474.
INFO
Published Date :
June 29, 2026, 8:16 p.m.
Last Modified :
June 29, 2026, 8:16 p.m.
Remotely Exploit :
Yes !
Source :
GitHub_M
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update Coolify to version 4.0.0-beta.474.
- Ensure webhook secrets are not null.
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