CVE-2026-50099 Overview
CVE-2026-50099 affects Naxclow device firmware, which prints sensitive WiFi association data in cleartext to an exposed Universal Asynchronous Receiver/Transmitter (UART) console during network setup. The firmware logs the host network's Service Set Identifier (SSID), Pre-Shared Key (PSK), and negotiated WiFi Protected Access (WPA) keys directly to the console. The UART pads are physically labeled on production hardware and use default serial settings. An interactive RT-Thread shell on the same interface permits arbitrary memory reads, enabling full firmware extraction. This issue is categorized under [CWE-538: Insertion of Sensitive Information into Externally-Accessible File or Directory].
Critical Impact
An attacker with brief physical access can recover host WiFi credentials and extract device firmware to bootstrap further attacks against the network and other devices.
Affected Products
- Naxclow device firmware (production hardware)
- Devices using RT-Thread shell over UART for diagnostics
- Outdoor-mounted Naxclow camera-class devices exposing labeled UART pads
Discovery Timeline
- 2026-06-12 - CVE-2026-50099 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2026-50099
Vulnerability Analysis
The vulnerability stems from verbose debug output left in production firmware. During the WiFi association sequence, the firmware emits the host SSID, the PSK, and the WPA keys negotiated during the four-way handshake. These values are written in cleartext to a UART interface that remains active on shipped devices.
The exposure is amplified by a second weakness on the same interface. The UART drops into an interactive RT-Thread shell that accepts commands permitting arbitrary memory reads. An attacker can therefore dump the device's flash contents and recover the full firmware image, keys, and any stored secrets.
Because Naxclow devices are frequently mounted outdoors, the attack window for brief physical access is realistic. An attacker only needs to remove the enclosure and attach a USB-to-serial adapter to the labeled pads to read the data stream and interact with the shell.
Root Cause
The root cause is improper exposure of sensitive information through a debug interface left enabled on production builds. The firmware fails to gate diagnostic logging and shell access behind authentication, signed unlock, or fuse-based disablement.
Attack Vector
The attack vector is physical. An adversary opens the device housing, connects to the labeled UART pads using default serial parameters, and either passively observes the credential-bearing log output or actively issues RT-Thread shell commands to read memory and extract firmware.
No verified exploit code is published for this issue. Refer to the CISA ICS Advisory and the GitHub CSAF Resource for vendor-coordinated technical details.
Detection Methods for CVE-2026-50099
Indicators of Compromise
- Physical evidence of enclosure tampering or removal on deployed Naxclow devices.
- Unexpected serial adapters, jumper wires, or test clips attached to UART pads.
- Unscheduled device reboots or WiFi re-association events that could correlate with attacker probing.
- Subsequent appearance of the host SSID or PSK in dumps, paste sites, or unauthorized network access logs.
Detection Strategies
- Inventory all Naxclow devices and flag units mounted in publicly accessible or outdoor locations for inspection.
- Audit wireless logs for unfamiliar clients associating with the same PSK after a suspected tamper event.
- Compare firmware hashes across the fleet to identify devices whose flash has been read or modified.
Monitoring Recommendations
- Monitor wireless controllers for repeated re-association attempts from device MAC addresses tied to outdoor units.
- Alert on new device fingerprints joining the network with credentials matching IoT segments.
- Enable physical tamper detection where supported, and review camera or sensor footage covering device locations.
How to Mitigate CVE-2026-50099
Immediate Actions Required
- Treat any host WiFi credentials configured on Naxclow devices as compromised if physical access cannot be ruled out, and rotate the affected SSID PSK.
- Move Naxclow devices to a dedicated, isolated WiFi SSID and VLAN with no lateral access to corporate or sensitive networks.
- Physically secure outdoor-mounted devices using tamper-evident enclosures and restrict access to UART pads.
- Track vendor advisories at the CISA ICS Advisory page for firmware updates that disable the debug console.
Patch Information
No vendor patch is referenced in the NVD record at publication. Coordinated advisory information is available through the CISA ICS Advisory and the corresponding CSAF document. Apply firmware updates as soon as the vendor releases a build that disables UART logging and the RT-Thread shell on production units.
Workarounds
- Segment Naxclow devices onto a guest or IoT VLAN with firewall rules blocking access to internal resources.
- Use a unique, single-purpose WiFi PSK for these devices so disclosure does not expose the primary corporate or home network.
- Apply tamper-evident seals over device enclosures and inspect them on a routine schedule.
- Where feasible, fill or cover the exposed UART pads with non-conductive epoxy to raise the cost of physical access.
# Example: isolate Naxclow devices on a dedicated SSID/VLAN (vendor-specific syntax)
# 1. Create a dedicated VLAN for IoT cameras
vlan 50
name iot-cameras
# 2. Restrict the VLAN from reaching internal subnets
ip access-list extended IOT_RESTRICT
deny ip 10.50.0.0 0.0.255.255 10.0.0.0 0.255.255.255
permit ip 10.50.0.0 0.0.255.255 any
# 3. Bind the ACL to the IoT VLAN interface
interface vlan 50
ip access-group IOT_RESTRICT in
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
