Cross-site scripting in Wiki.js - CVE-2021-43856
Published: December 26, 2021 / Updated: April 28, 2026
Vulnerability identifier: #VU128257
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Clear
CVE-ID: CVE-2021-43856
CWE-ID: CWE-79
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Requarks.io
Affected software:
Wiki.js
Wiki.js
Detailed vulnerability description
The vulnerability allows a remote user to execute arbitrary JavaScript in another user's browser.
The vulnerability exists due to stored cross-site scripting in non-image file uploads when viewing uploaded files inline in the browser. A remote user can upload a specially crafted file to execute arbitrary JavaScript in another user's browser.
The malicious file must be opened directly by the victim and does not trigger from a normal Wiki.js page.
How to mitigate CVE-2021-43856
Install security update from vendor's website.