CVE-2026-56181
Windows Network Address Translation (NAT) Spoofing Vulnerability
No known exploitation. EPSS puts it in the 18th percentile. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
What it is
From the CVE record
Origin validation error in Windows Network Address Translation (NAT) allows an unauthorized attacker to perform spoofing over an adjacent network.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
0.3% chance of exploitation activity in the next 30 days, which ranks it in the 18th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
10 events over 31 days, from the signal feeds we watch.
- Analysis publishedNatJack: The Same NAT Flaw Got Windows and Linux Patched — Cisco and Apple Call It a Feature
- Patch availablepatch available, record updated, record updated
- OpenVAS check added
- Publishedweakness classified, record updated, record updated
Affected products
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Scored 8.3 by NVD.
How it is reached
- Attack Vector AdjacentRequires access to the local network (e.g. same Wi-Fi, Bluetooth)
- Attack Complexity HighRequires specific conditions like a race condition or non-default configuration
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope ChangedThe exploit can affect other components (e.g. sandbox escape, host compromise from VM)
Impact if exploited
- Confidentiality HighTotal information disclosure — all data in the component is compromised
- Integrity HighTotal loss of integrity — attacker can modify any data in the component
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
Sources
References in the record
In the news
- ⚡ Weekly Recap: AI Goes Rogue, Metabase 0-Day, MCP Supply-Chain Attacks, and Router Backdoors
- New NatJack Attacks Hijack TCP Sessions and Spoof DNS by Manipulating NAT Tables
- Black Hat USA 2026 – Summary of Vendor Announcements (Part 4)
- Microsoft Patch Tuesday July 2026 - The AI Acopolypse is Here
- Microsoft July 2026 Patch Tuesday fixes massive 570 flaws, 3 zero-days
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