CVE-2026-34590

Postiz: SSRF via Webhook Creation Endpoint Missing URL Safety Validation

MEDIUM
5.4
CVSS Score
Published: April 2, 2026 at 05:26 PM UTC
Updated: July 24, 2026 at 09:20 PM UTC
2 products affected across 2 vendorsPostizPostiz

Using postiz-app by gitroomhq?

Get instant alerts when new vulnerabilities affect postiz-app - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM5.4
Exploit prediction
EPSS 0.2%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2.21.4
Affected range stops below 2.21.4, so it looks safe — our inference, not a vendor statement
v < 2.21.4
Affected range stops below 2.21.4, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

x_refsource_CONFIRMExploitMitigationVendor Advisory
Source: cverecord
https://github.com/gitroomhq/postiz-app/security/advisories/GHSA-wc9c-7cv8-m225
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/gitroomhq/postiz-app/releases/tag/v2.21.4

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.4MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-918

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card