PT-2026-29855 · Postiz · Postiz

Offset · CVE-2026-34590 · Published 2026-04-02 · Updated 2026-04-02

Positive Technologies (AI Summary)

CVSS v3.1

5.4

Medium

Base vector

AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Name of the Vulnerable Software and Affected Versions Postiz versions prior to 2.21.4

Description An issue exists in the creation of webhooks where the POST /webhooks/ endpoint fails to properly validate the url field. While it performs a format check, it lacks a validator to block internal or private network addresses. Consequently, when a post is published, the orchestrator retrieves the stored URL without runtime validation, allowing for blind Server-Side Request Forgery (SSRF)—a technique where an attacker forces a server to make requests to an internal resource—against internal services.

Recommendations Update to version 2.21.4. Avoid using the url parameter in the POST /webhooks/ endpoint to point to internal network addresses until the update is applied.

Exploit

Fix

SSRF

Weakness Enumeration

CWE-918

Related Identifiers

CVE-2026-34590

GHSA-WC9C-7CV8-M225

Affected Products

Postiz

References · 6

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34590.json · Exploit
• https://github.com/gitroomhq/postiz-app/security/advisories/GHSA-wc9c-7cv8-m225 · Vendor Advisory
• https://github.com/gitroomhq/postiz-app/commit/5ae4c950db6aa516a31454b7a45b9480bca40a11 · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-34590 · Security Note
• https://osv.dev/vulnerability/CVE-2026-34590 · Vendor Advisory
• https://github.com/gitroomhq/postiz-app/releases/tag/v2.21.4 · Note