What’s Vulnerable › Vulnerabilities

CVE-2026-55088: Etherpad: Device-to-device author-token transfer endpoint is replayable, never expires, and exposes the cleartext author token

• Severity: medium (CVSS 6.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-19 · updated 2026-09-09
• Weakness: CWE-200

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 products

• etherpad: from 2.6.0, < 3.1.0

References

• https://github.com/ether/etherpad/commit/8c6104c5d5daf41f0d454acc04d42dffa0e0d996
• https://github.com/ether/etherpad/pull/7784
• https://github.com/ether/etherpad/security/advisories/GHSA-vqfp-p66c-xrp9
• https://github.com/ether/etherpad/tree/3.1.0

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