CVE-2026-42889

Critical

Description

Relay adds real-time collaboration to Obsidian. Relay Server versions 0.9.0 through 0.9.6 contain an authentication bypass in the multi-document WebSocket endpoints. When authentication is configured, WebSocket connections without a token query parameter were incorrectly treated as having full server permissions. An unauthenticated network attacker who knows or guesses a document ID could connect to the document sync WebSocket and read or modify document contents without a valid document token. This vulnerability is fixed in 0.9.7.

SeverityCritical
CVSS9.1
Exploit probability—
ProductNo-instructions Relay-server
PublishedMay 12, 2026
First seenMay 12, 2026

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

ProductAffected versionsFixed in
No-Instructions relay-server>= 0.9.0, < 0.9.7—

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