by Kastro
Paper/Archive/CVE-2026-42556

CVE-2026-42556

gitroomhq postiz-app — Postiz stored XSS in public preview page

EPSS 0.3%CVSS 9.0
critical.is priorityof 100
31
CVSS 9.0 (NVD)9.0 / 10 × 3027.0Not in CISA KEV+300.0EPSS percentile 17.5.175 × 203.5No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

Postiz is an AI social media scheduling tool. From version 2.21.6 to before version 2.21.7, any authenticated user who can create a post can store arbitrary HTML in post content by tampering their own save request and send the public preview link /p/<postId>?share=true to another user. The preview page renders that stored HTML with dangerouslySetInnerHTML on the main application origin. This issue has been patched in version 2.21.7.

Affected

ProductAffectedFixed inSource
postiz-app>= 2.21.6, < 2.21.7–CNA

Scores by source

NVD9.0CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
GitHub_M (CNA)8.9CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: total

References

refgithub.com/gitroomhq/postiz-app/security/advisories/GHSA-hhxq-3wg7-4rj8refgithub.com/gitroomhq/postiz-app/releases/tag/v2.21.7