Is CVE-2026-55678 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-55678 being exploited in the wild.

How severe is CVE-2026-55678?

Medium severity, with a CVSS score of 4, published 28 August 2026.

Which products and versions are affected?

Basekick Labs Arc < 0.0.0-20260615160325-38402ad2ebdd; github.com/basekick-labs/arc (Go) < 0.0.0-20260615160325-38402ad2ebdd, SEMVER:introduced=0,fixed=0.0.0-20260615160325-38402ad2ebdd.

Is there a fix for CVE-2026-55678?

Yes. github.com/basekick-labs/arc (Go): upgrade to 0.0.0-20260615160325-38402ad2ebdd or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-55678 attacked?

It is attacked over the network.

Am I affected by CVE-2026-55678?

Check whether you run Basekick Labs Arc or github.com/basekick-labs/arc (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-55678: Arc Enterprise authentication bypass in cluster node admission

Q: Which products and versions are affected?

Basekick Labs Arc < 0.0.0-20260615160325-38402ad2ebdd; github.com/basekick-labs/arc (Go) < 0.0.0-20260615160325-38402ad2ebdd, SEMVER:introduced=0,fixed=0.0.0-20260615160325-38402ad2ebdd.

Q: Is there a fix for CVE-2026-55678?

Yes. github.com/basekick-labs/arc (Go): upgrade to 0.0.0-20260615160325-38402ad2ebdd or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-55678 attacked?

It is attacked over the network.

Q: Am I affected by CVE-2026-55678?

Check whether you run Basekick Labs Arc or github.com/basekick-labs/arc (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-55678 · Severity: medium · CVSS 4 · Published 2026-08-28

Arc Enterprise's clustering feature fails to authenticate join requests when the shared secret is not configured, allowing an unauthenticated network attacker to register a malicious node that will receive forwarded database queries and write operations along with credentials (bearer tokens, API keys). An attacker can then observe or intercept sensitive data, forge responses, or disrupt cluster operations. The vulnerability only affects deployments with clustering explicitly enabled; the default standalone configuration is unaffected.

Technologies: Basekick Labs Arc, github.com/basekick-labs/arc (Go). Vendors: Basekick Labs, Go.

Quick answers

Is CVE-2026-55678 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-55678 being exploited in the wild.
How severe is CVE-2026-55678?: Medium severity, with a CVSS score of 4, published 28 August 2026.
Which products and versions are affected?: Basekick Labs Arc < 0.0.0-20260615160325-38402ad2ebdd; github.com/basekick-labs/arc (Go) < 0.0.0-20260615160325-38402ad2ebdd, SEMVER:introduced=0,fixed=0.0.0-20260615160325-38402ad2ebdd.
Is there a fix for CVE-2026-55678?: Yes. github.com/basekick-labs/arc (Go): upgrade to 0.0.0-20260615160325-38402ad2ebdd or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-55678 attacked?: It is attacked over the network.
Am I affected by CVE-2026-55678?: Check whether you run Basekick Labs Arc or github.com/basekick-labs/arc (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

github.com/basekick-labs/arc (Go): upgrade to 0.0.0-20260615160325-38402ad2ebdd or later
```
go get github.com/basekick-labs/arc@v0.0.0-20260615160325-38402ad2ebdd
```

Technical details

The vulnerability is an authentication bypass in the cluster join mechanism. The coordinator validates HMAC-based authentication only when cluster.shared_secret is non-empty; if empty (the default when clustering is enabled), join requests proceed with only a cluster-name check. An attacker on the network can send a crafted JoinRequest message specifying attacker-controlled node_id, role, api_addr, and raft_addr fields. The coordinator accepts this, creates a healthy node entry in its registry, and routes subsequent operations to the attacker's advertised addresses, forwarding all original request headers including Authorization and x-api-key. Heartbeat messages are similarly unauthenticated. The code conditionally enforces shared-secret validation only for file replication; this inconsistency allows clustering to proceed without authentication despite clustering being a trust boundary. Network reachability to the coordinator port (default 9100) is required; the attacker must know or guess the cluster name (default "arc-cluster").

Affected products

Basekick Labs Arc < 0.0.0-20260615160325-38402ad2ebdd

Identifiers

CVE-2026-55678
GHSA-p378-jp5r-gpgw
GO-2026-6322

Timeline

2026-06-25: disclosed
2026-08-28: advisory: GitHub advisory published
2026-06-15: patched: Patch version 0.0.0-20260615160325-38402ad2ebdd

References

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