CVE-2026-42889Relay Server WebSocket authentication bypass when token is omitted
Updated under an hour ago ()
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It affects No-Instructions relay-server. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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
- 9.1 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- Weakness (CWE)
- CWE-863, CWE-639
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- May 13, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
No-Instructions relay-server no_instructions:relay_server (from the name) | from 0.9.0, < 0.9.7 | CNA record |
References
- https://github.com/No-Instructions/relay-server/security/advisories/GHSA-9vp9-8q9j-8mqmx-refsource-confirm
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.