Vulnerability · Published Aug 19, 2026 · Assigned by GitHub_M

CVE-2026-55090Etherpad: Stored XSS in HTML export via unescaped attribute-pool values

Medium 5.3

In plain English

A medium-severity cross-site scripting in etherpad from ether. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)5.3Medium

Exploit odds (30 days)0.5%top 54.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	ep_etherpad-lite	3.3.0	GHSA-2jp7-wwpg-3p9w

Affected products (as reported)

Vendor	Product	Versions
ether	etherpad	< 3.3.0

Weakness: CWE-79 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

References

https://github.com/ether/etherpad/security/advisories/GHSA-2jp7-wwpg-3p9w x_refsource_CONFIRM
https://github.com/ether/etherpad/pull/7905 x_refsource_MISC
https://github.com/ether/etherpad/commit/86c56cf827dd6e5ff1b6cd3760f87adc47f58bb1 x_refsource_MISC
https://github.com/ether/etherpad/releases/tag/v3.3.0 x_refsource_MISC