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CVE

CVE-2026-42889

Relay Server WebSocket authentication bypass when token is omitted
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CVE

CVE-2026-42889

Relay Server WebSocket authentication bypass when token is omitted

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.

Package Versions Affected

Package Version
patch Availability
No items found.

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CVSS Version

Severity
Base Score
CVSS Version
Score Vector
C
H
U
9.1
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
C
H
U
0
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
C
H
U
-

Related Resources

No items found.

References

https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42889.json, https://github.com/No-Instructions/relay-server/security/advisories/GHSA-9vp9-8q9j-8mqm, https://nvd.nist.gov/vuln/detail/CVE-2026-42889

Severity

9.1

CVSS Score
0
10

Basic Information

Base CVSS
9.1
EPSS Probability
0.00366%
EPSS Percentile
0.2997%
Introduced Version
bc24089391fab62a67d43b9081c22faed7e2b9cd
Fix Available
b15b026bf8a230e12f23ad1d1b48dc0d53ce010f

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