arc has unauthenticated cluster node admission when `cluster.shared_secret` is unset — GHSA-P378-JP5R-GPGW

Summary

## Summary Arc Enterprise clustering accepts cluster join requests without authentication when `cluster.enabled=true` but `cluster.shared_secret` is not configured. The coordinator validates HMAC authentication only if a shared secret is non-empty; otherwise, a network attacker who can reach the coordinator port can send a join request with attacker-controlled node addresses and role. Accepted nodes are marked…

Timeline

Published by source

2026-08-28

Risk context

• Reported severity or threat level: medium.
• Reported CVSS score: 6.9 out of 10.
• Review exposure for the affected product or family: go: github.com/basekick-labs/arc.

Product

go: github.com/basekick-labs/arc

What to do

General, cautious steps (verify details in the official source):

• Review exposure and plan remediation based on risk and environment.
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

Evidence and provenance

Canonical advisory ID

GHSA-P378-JP5R-GPGW

Source

GitHub

Vendor

GitHub

Published by source

2026-08-28

Last source activity

2026-08-28

Additional identifiers

CVE-2026-55678

Curated by

hlukh.ch

Related advisories and connections

These advisories are connected by shared CVE, product, vendor, source, or time signals.