Postiz is an AI social media scheduling tool. Prior to version 2.21.4, the POST /webhooks/ endpoint for creating webhooks uses WebhooksDto which validates the url field with only @IsUrl() (format check), missing the @IsSafeWebhookUrl validator that blocks internal/private network addresses. The update (PUT /webhooks/) and test (POST /webhooks/send) endpoints correctly apply @IsSafeWebhookUrl. When a post is published, the orchestrator fetches the stored webhook URL without runtime validation, enabling blind SSRF against internal services. This issue has been patched in version 2.21.4.
CVSS Score
5.4
EPSS Score
0.0
Published
2026-04-02