Critical 9.9Published Aug 19, 2026

CVE-2026-55089Etherpad: JWT `admin` claim presence-only check lets non-admin OAuth users invoke every Etherpad HTTP API endpoint

Updated under an hour ago (2026-10-19 10:10 UTC)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

Etherpad is a real-time collaborative editor. From 2.1.0 until 3.1.0, Etherpad's src/node/handler/APIHandler.ts authorizes requests to /api/2/* in the authorization_code OAuth path by using requiredClaims with the admin claim. This check requires only that the claim exists, while src/node/security/OAuth2Provider.ts issues admin: false for configured non-admin users. A non-admin user with a valid signed token can therefore invoke administrative functions including setHTML, setText, appendText, deletePad, copyPad, movePad, restoreRevision, anonymizeAuthor, listAllPads, and listAuthorsOfPad, allowing disclosure, modification, or deletion of pads across the instance. This issue is fixed in version 3.1.0.

CVSS: 9.9 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L
Weakness (CWE): CWE-863
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Aug 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

ether etherpad ether:etherpad (from the name)	from 2.1.0, < 3.1.0	CNA record

References

https://github.com/ether/etherpad/security/advisories/GHSA-qfmh-fph3-mw8qx-refsource-confirm
https://github.com/ether/etherpad/pull/7784x-refsource-misc
https://github.com/ether/etherpad/commit/8c6104c5d5daf41f0d454acc04d42dffa0e0d996x-refsource-misc
https://github.com/ether/etherpad/releases/tag/v3.1.0x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.