NoMachine: Remote code execution via heap overflow in mDNS parsing
Summary
A heap-based buffer overflow in the mDNS resource record parsing of NoMachine allows a network-adjacent attacker to execute code in the context of the service account. No authentication is required, and the attack requires the attacker to be on the same LAN or broadcast domain. The vendor's own description in the CVE record and ZDI differs in impact, so at least denial of service must be assumed.
Affected
- NoMachine 9.8.2_1 (listed in the CVE record)
- Full affected range: Unknown.
Fixed in
- NoMachine 10.1.7
- NoMachine 9.9.6
- NoMachine 8.27.1
- Vendor confirmation of this specific fix: Unverified.
Workaround
- No vendor workaround found.
- Restrict UDP 5353 (mDNS) to the network segments that require it.
- Keep NoMachine hosts off guest, visitor and IoT networks.
- Check with NoMachine whether mDNS can be disabled in configuration.
Exploitation
- No known exploitation in the wild.
- Not listed in CISA KEV.
- CISA SSVC: exploitation none, not automatable.
- No public PoC confirmed.
Our recommendation
- Inventory all NoMachine servers and clients, including version 9.8.2_1.
- Upgrade to 10.1.7, 9.9.6 or 8.27.1 (or the latest release) in your branch.
- Restrict UDP 5353 and the web service port TCP 4443 to required hosts only.
- Patch CVE-2026-114549 (ZDI-26-786) at the same time, and check whether TCP 4443 is reachable from the internet.
- Monitor NoMachine hosts for unusual service-account activity.
Public exploits
Links to third-party sites, not checked by us – exploit code can contain malware. Only use it in isolated test environments.
- Proof of concept on GitHub (1 repositories)
do4choo/CVE-2026-92208_remote_mDNS_overflow
Research sources
- ZDI-26-710 advisory www.zerodayinitiative.com
- NoMachine knowledge base (customers) www.nomachine.com
- NoMachine news www.nomachine.com
- ZDI-26-786 advisory (CVE-2026-114549) www.zerodayinitiative.com
- OpenCVE CVE-2026-92208 app.opencve.io
- Strix CVE-2026-92208 www.strix.ai
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 31 Oct 2026, 11:11.
Original description (NVD)
NoMachine mDNS Heap-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NoMachine. Authentication is not required to exploit this vulnerability. The specific flaw exists within the parsing of mDNS resource records. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the service account. Was ZDI-CAN-30982.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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