CVE-2026-41896 Coolify: Unauthenticated Deployment Trigger via Webhook HMAC Bypass with Null Secret
Unauthenticated attackers can forge webhook signatures using a null secret to trigger unauthorized deployments in Coolify.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-41896?
CVE-2026-41896 is a high-severity authentication bypass vulnerability in coollabsio coolify, published on 29 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-287
Which versions are affected by CVE-2026-41896?
How do I fix CVE-2026-41896?
No fix has been published for CVE-2026-41896 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-41896 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-41896 exists.
Sources
Also known as GHSA-w8wm-r924-f65v.