What is CVE-2026-42889?

CVE-2026-42889 is a critical-severity vulnerability in No-instructions Relay-server, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 9.1/10. Published 2026-05-12.

How severe is CVE-2026-42889?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Auth bypass in No-instructions Relay-server

CVE-2026-42889

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…

Vulnerability class: IDOR (Insecure Direct Object Reference)

EPSS: 0.001 (16.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

Affected products

No-instructions Relay-server — versions >= 0.9.0, < 0.9.7

Weakness classification (CWE)

References

security-advisories@github.com (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-42889?: CVE-2026-42889 is a critical-severity vulnerability in No-instructions Relay-server, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 9.1/10. Published 2026-05-12.
How severe is CVE-2026-42889?: Critical severity. CVSS v3 base score is 9.1 out of 10.