CVE-2026-42556

Postiz stored XSS in public preview page

At a glance

Severity: HIGH 8.9
EPSS: EPSS 0.26 % · percentile 17 (2026-10-27)
State: PUBLISHED
Published: 2026-05-08
Updated: 2026-05-13
Assigner: GitHub_M
NVD status: Analyzed

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.

Scores

Version	Score	Vector	Scored by
CVSS 3.1	HIGH 8.9	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L	GitHub_M
CVSS 3.1	HIGH 8.9	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L	NVD · security-advisories@github.com (Secondary)
CVSS 3.1	CRITICAL 9.0	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H	NVD · nvd@nist.gov (Primary)

Weaknesses (CWE)

CWE-79

European references

ENISA EUVD · EUVD-2026-28866
GCVE · GCVE-0-2026-42556

Affected configurations (NVD CPE)

cpe:2.3:a:gitroom:postiz:2.21.6:*:*:*:*:*:*:*

Affected products

Product	Versions
gitroomhq · postiz-app	affected >= 2.21.6, < 2.21.7

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD