{"id":"CVE-2026-55087","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-55087","generatedAt":"2026-10-28T01:19:23.455Z","title":"From 2.1.0 until 3.1.0, Etherpad uses the attacker-controlled x-proxy-path request header in src/node/hooks/express/admin.ts when substituting paths into HTML, JavaScript, and CSS under /admin without sanitization, Vary: x-proxy-path, or Cache-Control:…","description":"Etherpad is a real-time collaborative editor. From 2.1.0 until 3.1.0, Etherpad uses the attacker-controlled x-proxy-path request header in src/node/hooks/express/admin.ts when substituting paths into HTML, JavaScript, and CSS under /admin without sanitization, Vary: x-proxy-path, or Cache-Control: private, no-store. A shared proxy or CDN can cache the resulting response and serve attacker-injected script to an administrator. In src/node/hooks/express/specialpages.ts, version 3.0.0 also accepts a protocol-relative x-proxy-path value when constructing the /p/:pad/timeslider redirect, allowing redirection to an attacker-controlled host. The issues are exploitable when the deployment permits client-supplied x-proxy-path headers to reach Etherpad. This issue is fixed in version 3.1.0.","published":"2026-08-19T20:17:18.000Z","lastModified":"2026-09-09T21:16:00.000Z","status":"Deferred","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":6.1,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"},"cwe":["CWE-79","CWE-444","CWE-601"],"affected":[],"epss":{"score":0.00578,"percentile":0.47352,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.58%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/ether/etherpad/commit/8c6104c5d5daf41f0d454acc04d42dffa0e0d996","source":"security-advisories@github.com"},{"url":"https://github.com/ether/etherpad/pull/7784","source":"security-advisories@github.com"},{"url":"https://github.com/ether/etherpad/security/advisories/GHSA-fjgc-3mj7-8rg8","source":"security-advisories@github.com"},{"url":"https://github.com/ether/etherpad/tree/3.1.0","source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-55087","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}