CVE-2026-63116: Deepstreamio Deepstream.io

High severity, CVSS 8.8. EPSS: 0.5% chance of exploitation in the next 30 days.

deepstream is a server that allows clients and backend services to sync data, send messages and make rpcs at scale. From 10.1.0 until 10.1.1, src/services/permission/valve/rules-map.ts omits RECORD_ACTION.PATCH_MULTI from RULES_MAP. When an authenticated user sends a PATCH_MULTI record operation while permission.type is config, getRulesForMessage returns a null rule specification and ConfigPermission.canPerformAction treats the missing specification as an unconditional allow instead of applying RULE_TYPES.WRITE. Any authenticated user can therefore modify arbitrary protected records, corrupt application state, or cause service disruption; deployments using the default permission type none already allow all operations and are not additionally affected. This issue is fixed in version 10.1.1.

Affected products

• Deepstreamio Deepstream.io: from 10.1.0, before 10.1.1 (fixed in 10.1.1)

Published 2026-09-21. Last modified 2026-09-24.