Read the docs
TI-2026-39793 Aliases CVE-2026-55089

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

Priority HIGH 76CWE-863Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · Low
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-863.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00464 40th percentileScored 2026-11-07
Fix Fixed etherpad (ether): 3.1.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
etheretherpad2.1.0 to before 3.1.03.1.0Patch availableCNA
  • etherpad Vendorether Affected 2.1.0 to before 3.1.0 Fixed in 3.1.0 Patch available CNA

Remediation

  • Fix · CNA etherpad (ether) Fixed in 3.1.0

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-55089

References

Other 4

  • TI-2026-39789 Etherpad: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in etherpad-lite CVSS 3.1CRITICAL 9.6
  • TI-2026-39790 Link following in etherpad CVSS 3.1MEDIUM 4.2
  • TI-2009-04910 Session fixation in ether Catalyst::Plugin::Authentication CVSS 3.1CRITICAL 9.1
  • TI-2025-27313 Catalyst::Authentication::Credential::HTTP versions 1.018 and earlier for Perl use insecurely generated nonces CVSS 3.1HIGH 8.6
  • TI-2026-39792 Information disclosure in etherpad CVSS 3.1MEDIUM 6.8
  • TI-2026-39794 Etherpad: Stored XSS in HTML export via unescaped attribute-pool values CVSS 4.0MEDIUM 5.3
See all 7 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences