Relay Server WebSocket authentication bypass when token is omitted
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-639.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| No-Instructions | relay-server | 0.9.0 to before 0.9.7 | 0.9.7 | Patch available | CNA |
- relay-server VendorNo-Instructions Affected 0.9.0 to before 0.9.7 Fixed in 0.9.7 Patch available CNA
Remediation
- Fix · CNA relay-server (No-Instructions) Fixed in 0.9.7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-42889
References
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences