CVE-2026-28742: Naxclow Auth Bypass Vulnerability

CVE-2026-28742 Overview

CVE-2026-28742 affects Naxclow devices that rely on a uniform request-signing scheme built around a hard-coded, platform-wide salt embedded in every firmware image. Once the salt is extracted from any single device, an attacker can forge valid signatures for arbitrary device or account operations across the entire platform. The design lacks per-device keys, server-side nonce tracking, and replay protections. The control plane also transmits requests over plain HTTP, which enables interception and impersonation at scale. The weakness is tracked under CWE-321 (Use of Hard-coded Cryptographic Key) and is detailed in CISA ICS Advisory ICSA-26-162-02.

Critical Impact
A single firmware extraction yields a master signing secret that authorizes forged requests against any Naxclow device or account on the platform.

Affected Products

Naxclow devices (model and version details not enumerated in NVD data)
Firmware images that embed the platform-wide signing salt
Cloud control-plane endpoints accepting plain HTTP signed requests

Discovery Timeline

2026-06-12 - CVE-2026-28742 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database
2026-06-18 - EPSS probability recorded at 0.512%

Technical Details for CVE-2026-28742

Vulnerability Analysis

The vulnerability stems from cryptographic key management failure in the request authentication design. Naxclow firmware ships with a static salt value baked into every binary, and that salt is the sole secret input to the request signature algorithm. Because the salt is identical on every device, recovery from one unit compromises all units. The signing layer does not bind signatures to a unique device identity, session, or freshly issued server nonce.

The absence of replay protection compounds the issue. An attacker who captures a single valid signed request can resubmit it, or generate new requests with valid signatures, without detection. Control-plane traffic uses plain HTTP rather than TLS, so signatures and payloads transit the network in clear text. This combination converts a localized firmware secret into a platform-wide forgery primitive.

Impact spans confidentiality, integrity, and availability of device and account operations. Attackers can issue arbitrary commands, modify account state, hijack device ownership, or impersonate the backend in responses to victims.

Root Cause

The root cause is the use of a hard-coded cryptographic value shared across the entire product line, combined with a signing construction that omits per-device keys, server-validated nonces, and transport encryption.

Attack Vector

An attacker first obtains a firmware image through device extraction, vendor downloads, or over-the-air capture. Static analysis reveals the embedded salt. The attacker then constructs signed requests against the cloud API or intercepts HTTP traffic on any shared network path. No authentication credentials or user interaction are required to forge requests against arbitrary accounts.

The vulnerability is described in prose only because no verified proof-of-concept code has been published. Refer to the CISA advisory and the CSAF document for vendor coordination details.

Detection Methods for CVE-2026-28742

Indicators of Compromise

Unsigned or plain HTTP requests to Naxclow control-plane endpoints originating from unexpected source IP ranges
Repeated identical signed requests indicating signature replay against the same account or device identifier
Device or account state changes that do not correlate with legitimate user app sessions
Firmware images appearing on third-party file-sharing services, indicating salt extraction risk

Detection Strategies

Inspect outbound network traffic for cleartext HTTP calls to Naxclow API hosts and alert on unencrypted control-plane patterns
Correlate device command timestamps with authenticated user activity to surface out-of-band command issuance
Deploy network IDS rules to identify duplicate request signatures or anomalous request volumes targeting IoT cloud endpoints

Monitoring Recommendations

Capture full packet metadata for IoT network segments and retain for retrospective analysis of forged requests
Monitor DNS queries to Naxclow vendor domains from network segments not expected to host these devices
Track firmware version distribution across deployed devices to prioritize replacement of affected units

How to Mitigate CVE-2026-28742

Immediate Actions Required

Isolate Naxclow devices on a dedicated VLAN with no route to sensitive internal assets or the broader internet beyond required vendor endpoints
Block cleartext HTTP traffic from IoT segments at the perimeter where feasible and force outbound flows through inspected proxies
Inventory deployed Naxclow units and determine business necessity, decommissioning devices that are not essential

Patch Information

No vendor patch is referenced in the NVD record or CISA advisory at the time of publication. Customers should consult the CISA ICS Advisory ICSA-26-162-02 for updates and contact Naxclow directly for remediation guidance. Effective remediation requires firmware redesign to use per-device keys, server-issued nonces, and TLS for control-plane traffic.

Workarounds

Restrict device network reachability to the minimum vendor endpoints required for operation
Apply egress filtering to drop HTTP traffic from IoT segments and require encrypted alternatives where supported
Replace affected devices with vendor products that implement per-device cryptographic identities and authenticated transport
Rotate any account credentials or tokens that may have been used alongside the affected devices

bash

# Example egress filter to block cleartext HTTP from an IoT VLAN
iptables -I FORWARD -i vlan-iot -p tcp --dport 80 -j DROP
iptables -I FORWARD -i vlan-iot -p tcp --dport 443 -m conntrack --ctstate NEW -j ACCEPT