CVE-2026-34590: gitroomhq Postiz SSRF in webhook creation endpoint

CVE-2026-34590 · Severity: medium · CVSS 5.4 · Published 2026-04-02

Postiz is an AI-powered tool used for scheduling and managing social media posts. A security flaw in its webhook system allows an attacker to force the application to send requests to internal network services that are not intended to be public. This could lead to the exposure of sensitive internal data, unauthorized interaction with private infrastructure, or the theft of cloud environment credentials.

Technologies: Gitroom Postiz. Vendors: Gitroom.

Quick answers

Is CVE-2026-34590 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-34590 being exploited in the wild.
How severe is CVE-2026-34590?
Medium severity, with a CVSS score of 5.4, published 2 April 2026.
Which products and versions are affected?
Gitroom Postiz < 2.21.4.
Is there a fix for CVE-2026-34590?
A patch was published on 2026-03-29: Fix developed and version 2.21.4 released. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-34590 attacked?
It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-34590?
Check whether you run Gitroom Postiz at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A Server-Side Request Forgery (SSRF) vulnerability exists in Postiz due to insufficient validation of webhook URLs during the creation process. While the update and test endpoints utilize the '@IsSafeWebhookUrl' validator, the initial creation endpoint (POST /webhooks/) only performs a basic format check using '@IsUrl()'. This allows an authenticated attacker to register webhooks pointing to internal or private IP addresses, such as 127.0.0.1 or cloud metadata services (169.254.169.254). When a social media post is subsequently published, the backend orchestrator triggers the stored URL without further validation. This results in a persistent, blind SSRF that can be used for internal port scanning or interacting with unauthenticated internal APIs. The vulnerability is resolved in version 2.21.4 by applying the safety validator to the creation DTO.

Affected products

  • gitroomhq Postiz < 2.21.4

Timeline

  • 2026-03-28: disclosed: Postiz received the advisory from a researcher.
  • 2026-03-29: patched: Fix developed and version 2.21.4 released.
  • 2026-04-02: advisory: CVE-2026-34590 published.

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.