Skip to content
Patch Next
Sign inAdd to your agent

← Actionable
Medium, CVSS 6.9amended

arc has unauthenticated cluster node admission when cluster.shared_secret is unset

CVE-2026-55678GHSA-p378-jp5r-gpgw

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (github.com/basekick-labs/arc 0.0.0-20260615160325-38402ad2ebdd), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

Add to your agent

Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
6.9 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N · score source
EPSS
  • CVE-2026-55678: 0.66% estimated exploitation activity in the next 30 days; percentile 51.82 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary Arc Enterprise clustering accepts cluster join requests without authentication when cluster.enabled=true but cluster.sharedsecret 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 healthy, registered locally or added as Raft voters, and can be selected by the cluster router for forwarded authenticated requests. Details Cluster defaults include an empty shared secret and TLS disabled: - internal/config/config.go:943-950 defaults cluster.enabled=false, cluster.clustername="arc-cluster", and cluster.coordinatoraddr=":9100". - internal/config/config.go:1001-1005 defaults cluster.sharedsecret="" and cluster.tlsenabled=false. Startup requires a shared secret only for file replication, not for all clustering/join/routing use: - cmd/arc/main.go:1258-1265 hard-fails…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 4 · amended ·

    Amended from ghsa record GHSA-p378-jp5r-gpgw

  2. Revision 3 · amended ·

    Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

  3. Revision 2 · amended ·

    Amended from osv record GO-2026-6322

  4. Revision 1 · created ·

    Published from osv record GHSA-p378-jp5r-gpgw

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-55678

Advisory: arc has unauthenticated cluster node admission when `cluster.shared_secret` is unset
IDs: CVE-2026-55678, GHSA-p378-jp5r-gpgw
Record: https://patchnext.com/advisories/cve-2026-55678 (revision 4, source checked 26 Oct 2026, 15:28 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/basekick-labs/arc 0.0.0-20260615160325-38402ad2ebdd. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/basekick-labs/arc: affected < 0.0.0-20260615160325-38402ad2ebdd; fixed in 0.0.0-20260615160325-38402ad2ebdd

## Suggested inspection (read-only)
- Go github.com/basekick-labs/arc: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/basekick-labs/arc.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-p378-jp5r-gpgw (OSV record GHSA-p378-jp5r-gpgw lists affected ranges: Go github.com/basekick-labs/arc >=0 <0.0.0-20260615160325-38402ad2ebdd (fixed))
- Verified: https://osv.dev/vulnerability/GO-2026-6322 (OSV record GO-2026-6322 lists affected ranges: Go github.com/basekick-labs/arc >=0 <0.0.0-20260615160325-38402ad2ebdd (fixed))
- Verified: https://github.com/advisories/GHSA-p378-jp5r-gpgw (GitHub-reviewed advisory GHSA-p378-jp5r-gpgw lists affected ranges: Go github.com/basekick-labs/arc >=0 <0.0.0-20260615160325-38402ad2ebdd)

Commands are suggestions: review each one before running it.

Loading voting…