Vulnerability details
CVE-2026-42889
No-Instructions relay-server
Relay Server WebSocket authentication bypass when token is omitted
CVSS 3.1
9.1Critical
Official 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.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 9.1Critical | 3.1 | CVEProject cvelistV5 (CNA) (GitHub_M) | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| No-Instructions | relay-server | >= 0.9.0, < 0.9.7 | CVEProject cvelistV5 (CNA) |
References and advisories
1
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Details
- Published
- 2026-05-12
- Last updated
- 2026-05-13
- State
- Published
- Assigner (CNA)
- GitHub_M
Exploit prediction (EPSS)
0.36%
Probability of exploitation in 30 days
30.6%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- Proof of concept
- Technical impact
- Total
Weaknesses (CWE)
- CWE-863Incorrect Authorization
- CWE-639Authorization Bypass Through User-Controlled Key