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

published 2026-08-13 2 mo ago modified 2026-09-09 1 mo ago also GHSA-vqfp-p66c-xrp9 , EUVD-2026-62725

cvss: 6.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 38%
public exploits: 0; none known

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.

Patch / fix

fixed in 1 links 2

npm ep_etherpad-lite 3.1.0

github.com/ether/etherpad@8c6104c commit
github.com/ether/etherpad#7784 pull request

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 2 mo ago (2026-08-21)

Exploit prediction

0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.8	CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
GitHub	3.1	6.8	CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

Affected packages

ecosystem	package	affected	fixed in
npm	ep_etherpad-lite	>=2.6.0, <3.1.0	3.1.0

Affected products

ether etherpad

Classification

Weakness

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

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary