Critical severity · published May 8, 2026
CVE-2026-42556
Postiz stored XSS in public preview page
9.0
CVSS
0.3%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Confidentiality
High
Integrity
High
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 17% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PO
postiz-app · gitroomhq
>= 2.21.6, < 2.21.7 · source: vendor
PO
Postiz · Gitroom
2.21.6 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-42556
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-42556
Product
https://github.com/gitroomhq/postiz-app/releases/tag/v2.21.7
Vendor Advisory
https://github.com/gitroomhq/postiz-app/security/advisories/GHSA-hhxq-3wg7-4rj8
More from postiz-app
9.9
CVE-2026-115933
Forged signed tokens let any registered user take over other users and organizations
9.9
CVE-2026-115931
Arbitrary file read and backend crash through unrestricted provider method calls
9.9
CVE-2026-48781
Postiz has cross-tenant SUPERADMIN takeover via Skool-provider JWT forgery
9.8
CVE-2026-19264
Unauthenticated arbitrary file read via /uploads path traversal (URL-encoded separators) leading to instance takeover
9.8
CVE-2026-42298
Postiz: Arbitrary Code Execution and Token Exfiltration in pr-docker-build.yml via untrusted Dockerfile.dev