CVE-2026-55088 PUBLISHED

Etherpad: Device-to-device author-token transfer endpoint is replayable, never expires, and exposes the cleartext author token

Assigner: GitHub_M
Reserved: 16.06.2026 Published: 19.08.2026 Updated: 19.08.2026

Etherpad is a real-time collaborative editor. From 2.6.0 until 3.1.0, Etherpad's src/node/hooks/express/tokenTransfer.ts uses POST /tokenTransfer to store an author token for transfer between browsers and exposes it through GET /tokenTransfer/{uuid}. Although the record includes createdAt, the transfer has no expiration check, is not removed after successful redemption, and is returned by res.send(tokenData), including the raw author token. An unauthenticated attacker who obtains a transfer UUID can repeatedly redeem it, receive fresh author cookies, read the cleartext token, and impersonate the originating author for pad read and write operations. This issue is fixed in version 3.1.0.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
CVSS Score: 6.8

Product Status

Vendor ether
Product etherpad
Versions
  • Version >= 2.6.0, < 3.1.0 is affected

References

Problem Types

  • CWE-200: Exposure of Sensitive Information to an Unauthorized Actor CWE
  • CWE-294: Authentication Bypass by Capture-replay CWE