Cross-site scripting in Etherpad - CVE-2026-55090
Published: September 22, 2026
Vulnerability identifier: #VU151605
CSH Severity: Low
CVSS v4: 5.1 [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]
CVE-ID: CVE-2026-55090
CWE-ID: CWE-79
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to execute arbitrary JavaScript in a collaborator's browser.
The vulnerability exists due to improper neutralization of input during web page generation in the getHTMLFromAtext function in src/node/utils/ExportHtml.ts when exporting pad content to HTML. A remote user can inject crafted attribute-pool values into a pad to execute arbitrary JavaScript in a collaborator's browser.
User interaction is required for a collaborator to open the HTML export.
Affected software
Etherpad
How to mitigate CVE-2026-55090
Install security update from vendor's website.
Etherpad - update to 3.3.0