CVE-2026-42889— Relay Server WebSocket authentication bypass when token is omitted
Possible ATT&CK Techniques 1AI
T1190 · Exploit Public-Facing ApplicationAffected Version Matrix 1
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| No-Instructions | relay-server | >= 0.9.0, < 0.9.7 | affected |
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I. Basic Information for CVE-2026-42889
Vulnerability Information
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Vulnerability Title
Relay Server WebSocket authentication bypass when token is omitted
Source: NVD (National Vulnerability Database)
Vulnerability 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.
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Source: NVD (National Vulnerability Database)
Vulnerability Type
授权机制不正确
Source: NVD (National Vulnerability Database)
Vulnerability Title
Relay Server 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Relay Server是System 3开源的一个支持离线协作的实时文档同步服务器。 Relay Server 0.9.0版本至0.9.6版本存在安全漏洞，该漏洞源于多文档WebSocket端点中，未提供令牌查询参数的WebSocket连接被错误地视为具有完全服务器权限，可能导致未经身份验证的攻击者读取或修改文档内容。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| No-Instructions | relay-server | >= 0.9.0, < 0.9.7 | - |
II. Public POCs for CVE-2026-42889
| # | POC Description | Source Link | Shenlong Link |
|---|
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IV. Related Vulnerabilities
Same weakness: CWE-863
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