Description
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.
Affected products
gitroom: postiz
References3
- github.com/gitroomhq/postiz-app/security/advisories/GHSA-wc9c-7… ExploitMitigationVendor Advisory
- github.com/gitroomhq/postiz-app/commit/5ae4c950db6aa516a31454b7… Patch
- github.com/gitroomhq/postiz-app/releases/tag/v2.21.4 ProductRelease Notes
Metrics
- CVSS 3.1
-
5.4
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - EPSS — exploit probability
- 0% percentile: 14 · as of 12 November 2026
- CWE
- CWE-918
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.