CVE-2026-55089

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 3.1

9.9CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

EPSS

0.5% chance of exploitation in the next 30 days; higher than 39% of CVEs (scores of 2026-10-25)

CWE

CWE-863

Published

2026-08-19

Modified

2026-10-24

Record from

the NVD, synced 2026-10-24

References

• https://github.com/ether/etherpad/commit/8c6104c5d5daf41f0d454acc04d42dffa0e0d996
• https://github.com/ether/etherpad/pull/7784
• https://github.com/ether/etherpad/releases/tag/v3.1.0
• https://github.com/ether/etherpad/security/advisories/GHSA-qfmh-fph3-mw8q
• https://github.com/ether/etherpad/security/advisories/GHSA-qfmh-fph3-mw8q

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