ether Etherpad up to 3.2.x Export ExportHtml.ts getHTMLFromAtext cross site scripting

Summaryinfo

A vulnerability was found in ether Etherpad up to 3.2.x and classified as problematic. Affected by this vulnerability is the function getHTMLFromAtext of the file src/node/utils/ExportHtml.ts of the component Export. Such manipulation leads to cross site scripting. This vulnerability is traded as CVE-2026-55090. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in ether Etherpad up to 3.2.x and classified as problematic. Affected by this issue is the function getHTMLFromAtext of the file src/node/utils/ExportHtml.ts of the component Export. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. CVE summarizes:

Etherpad is a real-time collaborative editor. Prior to 3.3.0, getHTMLFromAtext in src/node/utils/ExportHtml.ts interpolates values from the exportHtmlAdditionalTagsWithData plugin hook into span data attributes without HTML attribute escaping. A pad editor can place an attacker-controlled value into the attribute pool through moveOpsToNewPool and AttributePool.putAttrib. When a bundled plugin such as ep_font_color or ep_font_size registers the hook, opening the resulting HTML export causes the value to execute as stored cross-site scripting in the Etherpad origin. This issue is fixed in version 3.3.0.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-55090 since 06/16/2026. The exploitation is known to be easy. The attack may be launched remotely. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 3.3.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-62734). Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• ether

Name

• Etherpad

Version

• 3.0
• 3.1
• 3.2

Website

• Product: https://github.com/ether/etherpad/

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Once again VulDB remains the best source for vulnerability data.

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