{"id":"CVE-2026-55090","aliases":["EUVD-2026-62734","GHSA-2jp7-wwpg-3p9w"],"status":"published","title":"Etherpad: Stored XSS in HTML export via unescaped attribute-pool values","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.","severity":{"version":"4.0","score":5.3,"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","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00547,"percentile":0.46193,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-79"],"published":"2026-08-17T17:49:38Z","modified":"2026-11-11T02:49:05Z","fixes":[{"ecosystem":"npm","package":"ep_etherpad-lite","fixed_in":["3.3.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"ep_etherpad-lite","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"1.8.14"},{"fixed":"3.3.0"}]}]},{"source":"osv","ecosystem":"npm","package":"ep_etherpad-lite","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.3.0"}]}]}],"products":[{"vendor":"ether","product":"etherpad"}],"references":[{"url":"https://github.com/ether/etherpad/security/advisories/GHSA-2jp7-wwpg-3p9w","tags":["x_refsource_CONFIRM","advisory","web"]},{"url":"https://github.com/ether/etherpad/pull/7905","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/ether/etherpad/commit/86c56cf827dd6e5ff1b6cd3760f87adc47f58bb1","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/ether/etherpad/releases/tag/v3.3.0","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/ether/etherpad/releases/tag/3.3.0","tags":["web"]},{"url":"https://github.com/advisories/GHSA-2jp7-wwpg-3p9w"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55090.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55090","tags":["advisory"]},{"url":"https://github.com/ether/etherpad","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-55090","title":"Etherpad: Stored XSS in HTML export via unescaped attribute-pool values","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.","status":"published","published":"2026-08-19T19:32:17.607Z","modified":"2026-08-20T12:39:30.3Z","cvss":[{"version":"4.0","score":5.3,"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","level":"medium","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:20:12.260247Z"}],"euvd":[{"id":"EUVD-2026-62734","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.","status":"published","published":"2026-08-19T19:32:17Z","modified":"2026-08-20T12:39:30Z","cvss":[{"version":"4.0","score":5.3,"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","level":"medium"}],"updated_at":"2026-11-02T18:01:40.451894Z"}],"ghsa":[{"id":"GHSA-2jp7-wwpg-3p9w","title":"Etherpad has stored XSS in HTML export via unescaped attribute-pool values","description":"Fix: PR #7905 (ether/etherpad).\n\n`getHTMLFromAtext` in `src/node/utils/ExportHtml.ts` interpolates values from the `exportHtmlAdditionalTagsWithData` plugin hook into `span data-\u003ck\u003e=\"\u003cv\u003e\"` without HTML-attribute escaping. The value comes verbatim from the pad attribute pool, which a pad editor controls via a crafted changeset (only `author` attributes are validated; `moveOpsToNewPool` -\u003e `AttributePool.putAttrib` stores any value). With a bundled plugin that registers the hook (ep_font_color / ep_font_size), an attribute value such as `\" onload=\"alert(1)` is exported as `\u003cspan data-color=\"\" onload=\"alert(1)\"\u003e` and served as text/html, yielding stored XSS for any collaborator who opens the export.\n\nFix: escape the name and value via `Security.escapeHTMLAttribute`. PR #7905 also adds a startup warning when default/placeholder account or SSO credentials are configured (defense-in-depth, non-breaking).","status":"published","published":"2026-08-17T17:49:38Z","modified":"2026-08-17T17:49:39Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:41:01.23108Z"}],"nvd":[{"id":"CVE-2026-55090","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.","status":"published","published":"2026-08-19T20:17:18.233Z","modified":"2026-09-09T21:15:59.613Z","cvss":[{"version":"4.0","score":5.3,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:12:39.962615Z"}],"osv":[{"id":"CVE-2026-55090","title":"Etherpad: Stored XSS in HTML export via unescaped attribute-pool values","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.","status":"published","published":"2026-08-19T19:32:17.607Z","modified":"2026-11-11T02:49:05.381235281Z","cvss":[{"version":"4.0","score":5.3,"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","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-11T03:21:18.82478Z"},{"id":"GHSA-2jp7-wwpg-3p9w","title":"Etherpad has stored XSS in HTML export via unescaped attribute-pool values","description":"Fix: PR #7905 (ether/etherpad).\n\n`getHTMLFromAtext` in `src/node/utils/ExportHtml.ts` interpolates values from the `exportHtmlAdditionalTagsWithData` plugin hook into `span data-\u003ck\u003e=\"\u003cv\u003e\"` without HTML-attribute escaping. The value comes verbatim from the pad attribute pool, which a pad editor controls via a crafted changeset (only `author` attributes are validated; `moveOpsToNewPool` -\u003e `AttributePool.putAttrib` stores any value). With a bundled plugin that registers the hook (ep_font_color / ep_font_size), an attribute value such as `\" onload=\"alert(1)` is exported as `\u003cspan data-color=\"\" onload=\"alert(1)\"\u003e` and served as text/html, yielding stored XSS for any collaborator who opens the export.\n\nFix: escape the name and value via `Security.escapeHTMLAttribute`. PR #7905 also adds a startup warning when default/placeholder account or SSO credentials are configured (defense-in-depth, non-breaking).","status":"published","published":"2026-08-17T17:49:38Z","modified":"2026-08-17T18:11:04.67332Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:46:34.338541Z"}]}}