Sources: National Vulnerability Database, CVE.org, CISA KEV, FIRST EPSS
CVE-2026-123998 Overview
Hisense VIDAA Smart TV firmware V0000.01.00a.P0220 contains an authentication bypass vulnerability in its remote-control MQTT broker on TCP port 36669, which accepts publicly documented default credentials and an ineffective 4-digit pairing PIN with no rate limiting or lockout, allowing a brute force of the entire code space in about five seconds, while some actions require no pairing at all. A LAN-adjacent attacker can exploit this to inject key events, change volume, switch input sources, enumerate inputs, launch arbitrary installed applications, and monitor pairing activity, posing a significant risk in hotel deployments where untrusted LAN access is common.
Critical Impact
Affected Products
- Hisense VIDAA Smart TV firmware: see the vendor advisory for the exact affected versions
Discovery Timeline
- 2026-11-06: CVE-2026-123998 published to the National Vulnerability Database by disclosure@vulncheck.com
- 2026-11-06: last updated in the NVD database
Technical Details for CVE-2026-123998
Vulnerability Analysis
CVE-2026-123998 is a Security Vulnerability weakness (CWE-307, CWE-1392) in Hisense VIDAA Smart TV firmware. Based on its CVSS vector, the flaw needs local or adjacent access, needs no login, and needs no user interaction.
With a CVSS base score of 7.2, apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Root Cause
The vendor description states: Hisense VIDAA Smart TV firmware V0000.01.00a.P0220 contains an authentication bypass vulnerability in its remote-control MQTT broker on TCP port 36669, which accepts publicly documented default credentials and an ineffective 4-digit pairing PIN with no rate limiting or lockout, allowing a brute force of the entire code space in about five seconds, while some actions require no pairing at all. A LAN-adjacent attacker can exploit this to inject key events, change volume, switch input sources, enumerate inputs, launch arbitrary installed applications, and monitor pairing activity, posing a significant risk in hotel deployments where untrusted LAN access is common.
Attack Vector
Based on the CVSS vector, the flaw needs local or adjacent access, needs no login, and needs no user interaction. Attack complexity is low complexity.
No exploitation in the wild is confirmed by CISA at the time of the last update. Check the references below for any vendor or researcher proof of concept.
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Detection Methods for CVE-2026-123998
Detection Strategies
- Inventory every instance of Hisense VIDAA Smart TV firmware and compare the running version with the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Run an authenticated vulnerability scan once your scanner ships a check for this CVE.
Monitoring Recommendations
- Forward Hisense VIDAA Smart TV firmware application, access and audit logs to your SIEM for retrospective hunting.
- Alert on new processes, configuration changes or outbound connections from the affected service.
- Track the vendor advisory and the CISA KEV catalog for changes in exploitation status.
How to Mitigate CVE-2026-123998
Immediate Actions Required
- Apply the fixed version of Hisense VIDAA Smart TV firmware named in the vendor advisory.
- Prioritize internet facing and business critical instances first.
- Rescan after the change to confirm the exposure is closed.
Patch Information
Use the fixed version listed in the vendor advisory for Hisense VIDAA Smart TV firmware.
Workarounds
- If patching must wait, restrict network access to the affected service and place it behind authentication or a web application firewall rule.
CWE References
Technical References
This entry is built directly from NVD, CISA KEV and EPSS data. Verify fixed versions in the vendor advisory before you deploy.
Frequently asked questions
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