CVE-2026-48106 Overview
CVE-2026-48106 affects Arc Enterprise, an open, SQL-native time-series database used for telemetry workloads. The cluster replication receiver at internal/cluster/replication/receiver.go validates only the wire-format envelope of inbound messages. The MsgReplicateSync payload is accepted without application-layer authentication. No HMAC, digital signature, or per-message nonce is applied. Transport-layer TLS or mTLS protects the stream, but any peer already on the cluster network can tamper with or replay replication messages. The vulnerability is tracked under CWE-306: Missing Authentication for Critical Function and is fixed in Arc version 2026.06.1.
Critical Impact
An attacker with cluster network access can tamper with or replay replication traffic, compromising the integrity of stored telemetry data across Arc Enterprise nodes.
Affected Products
- Arc Enterprise versions prior to 2026.06.1
- Basekick Labs Arc time-series database (cluster mode)
- Deployments using internal/cluster/replication/receiver.go replication handler
Discovery Timeline
- 2026-08-21 - CVE-2026-48106 published to NVD
- 2026-08-26 - Last updated in NVD database
Technical Details for CVE-2026-48106
Vulnerability Analysis
Arc Enterprise supports clustered deployments in which nodes exchange telemetry data through a replication protocol. The receiver component parses inbound frames and dispatches them to handlers based on opcode. During this dispatch, only the wire-format envelope is validated — specifically the length field and opcode identifier. The MsgReplicateSync message body carrying replicated writes is then processed without further authentication checks.
Because the payload lacks an HMAC, signature, or nonce, the receiver cannot distinguish between legitimate messages from an authorized peer and forged or replayed messages injected by an attacker on the cluster network. TLS or mTLS at the transport layer protects data in transit but does not bind the application payload to a trusted producer.
Root Cause
The root cause is missing authentication for a critical function [CWE-306]. Arc's design assumed the transport layer alone would be sufficient trust. Once a peer sits on the cluster network — through a compromised node, misconfigured firewall, or lateral movement — it can produce replication messages the receiver treats as authoritative.
Attack Vector
Exploitation requires network access to the cluster replication channel and low privileges on that network segment. An attacker who reaches the replication port can craft MsgReplicateSync messages that pass envelope validation and are applied to the target node's state. Replay of prior legitimate frames is likewise unrestricted, allowing overwrite of newer data with stale content. The result is integrity compromise of stored telemetry across replicating nodes without triggering authentication failures.
Because no code examples were released with the advisory, refer to the GitHub Security Advisory GHSA-wfgr-8x84-22q7 for the technical write-up.
Detection Methods for CVE-2026-48106
Indicators of Compromise
- Unexpected MsgReplicateSync frames arriving from source addresses not on the approved peer list.
- Replication log entries showing writes to shards or partitions the source node does not own.
- Divergence between telemetry values on peer nodes for identical timestamps and series keys.
Detection Strategies
- Enable verbose replication logging and alert on MsgReplicateSync from non-allowlisted peer identities or IPs.
- Compare checksums or content hashes of replicated shards across nodes to detect silent tampering.
- Deploy network monitoring on the cluster replication port to identify sessions from unexpected origins.
Monitoring Recommendations
- Forward Arc cluster replication logs to a centralized analytics platform for correlation with network flow data.
- Track baselines for replication message volume per peer and alert on statistical anomalies.
- Monitor firewall and east-west traffic policies for changes that expose the cluster port to untrusted segments.
How to Mitigate CVE-2026-48106
Immediate Actions Required
- Upgrade Arc Enterprise to version 2026.06.1 or later, which introduces application-layer authentication for replication messages.
- Restrict cluster network access to known-trusted peers using strict firewall or network policy rules.
- Audit historical replication logs for unexpected MsgReplicateSync traffic that may indicate prior tampering.
Patch Information
Basekick Labs fixed the issue in Arc version 2026.06.1. The patch adds application-layer validation to MsgReplicateSync payloads so replicated writes are bound to an authenticated peer identity. Details are available in the GitHub Security Advisory GHSA-wfgr-8x84-22q7.
Workarounds
- Restrict cluster network access with strict firewall rules that permit only known peer IP addresses on the replication port.
- Audit replication logs continuously for unexpected MsgReplicateSync traffic patterns.
- Disable cluster mode and operate in single-node configuration until the patched release is deployed.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
