CVE-2026-123204

Description

Posta before v0.18.0 contains a server-side request forgery vulnerability that allows authenticated users with edit rights to make the backend send POST requests to internal destinations by creating webhooks with arbitrary URLs. Attackers can target loopback, private-network or cloud metadata addresses and read delivery status codes and error strings to probe internal hosts and ports.

References

• https://github.com/goposta/posta/blob/8c3cb6f89c8a992329fac21491c38aed70d05c73/internal/services/webhook/dispatcher.go#L321-L338
• https://github.com/goposta/posta/commit/6bb376b55dcfdcb979040ed42c4bf57b99e4f46a
• https://github.com/goposta/posta/issues/282
• https://github.com/goposta/posta/pull/315
• https://github.com/goposta/posta/releases/tag/v0.18.0