Arc Enterprise cluster replication accepts unauthenticated MsgReplicateSync messages, enabling cluster-wide data injection from any TLS-trusted peer (CVE-2026-48106) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-48106

Arc Enterprise cluster replication accepts unauthenticated MsgReplicateSync messages, enabling cluster-wide data injection from any TLS-trusted peer

Answer in brief

CVE-2026-48106 records a Unknown severity vulnerability in Arc Enterprise cluster replication accepts unauthenticated MsgReplicateSync messages, enabling cluster-wide data injection from any TLS-trusted peer. The current sources do not mark it as known exploited. The current feed maps Basekick-Labs/arc (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 21, 2026Updated Aug 21, 2026Source checked Aug 22, 2026First seen by HOL Aug 21, 2026Material review Aug 21, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Basekick-Labs/arc (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Basekick-Labs/arcgeneric	< 2026.06.1	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Basekick-Labs/arc.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Aug 21, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 21, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 21, 2026

Sources and claim methodology

GitHub security advisorygithub.com

Upstream source description

Arc is an open, SQL-native time-series database for telemetry. Prior to version 26.06.1, Arc Enterprise's cluster replication receiver at `internal/cluster/replication/receiver.go` validates only the wire-format envelope (length, opcode) of inbound messages. The `MsgReplicateSync` payload itself is accepted without any application-layer authentication — no HMAC, no signature, no per-message nonce. The replication stream is protected at the transport layer by TLS / mTLS, but there is no protection against application-layer message tampering or replay once a peer is on the cluster network. This is fixed in 2026.06.1. Some workarounds are available. Restrict cluster network access to known-trusted peers via strict firewall rules, audit replication logs for unexpected `MsgReplicateSync` traffic, and/or disable cluster mode until the fix is available.

Quoted source text, attributed separately from HOL analysis.