Postiz: Unauthenticated arbitrary lifetime PRO grant via Nowpayments webhook

published 2026-07-15 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-44712

cvss: 7.7; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 12%
public exploits: 0; none known

Postiz is an AI social media scheduling tool. Prior to 2.21.8, Postiz fails to verify Nowpayments IPN callback authenticity against the payment provider shared secret and reads the target subscription identifier from the untrusted request body, allowing a low-privileged account to grant arbitrary organizations lifetime PRO subscriptions without payment. This issue is fixed in version 2.21.8.

Patch / fix

links 2

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 3 mo ago (2026-07-15)

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.7	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N

Affected products

gitroomhq postiz-app

Classification

Weakness

CWE-345 Insufficient Verification of Data Authenticity
CWE-639 Authorization Bypass Through User-Controlled Key

References

Sources

CVE List CVE-2026-48799
NVD CVE-2026-48799

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary