Authentication bypass in Relay Server WebSocket endpoints (CVE-2026-42889)

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. Affected versions: - >= 0.9.0, <= 0.9.6 We recommend updating to: 0.9.7. CVSS 9.1 · our assessment: act_now Reference: https://github.com/No-Instructions/relay-server/security/advisories/GHSA-9vp9-8q9j-8mqm Details: https://vuln.today/cve/CVE-2026-42889