CVE-2026-55088

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

MEDIUM
6.8
CVSS Score
Published: August 19, 2026 at 07:30 PM UTC
Updated: September 9, 2026 at 09:27 PM UTC
1 product affected across 1 vendorEtherpad

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Severity
MEDIUM6.8
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.1.0
Affected range stops below 3.1.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.8MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-200CWE-294

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