CVE-2026-42556
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.26%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 9.0 CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
- EPSS
- 0.26% probability · 18th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-79
- Affected
- gitroom/postiz
- Source
- security-advisories@github.com
References
- https://github.com/gitroomhq/postiz-app/releases/tag/v2.21.7Product, Release Notes
- https://github.com/gitroomhq/postiz-app/security/advisories/GHSA-hhxq-3wg7-4rj8Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.