CVE-2026-33921
MediumCVSS 5.2Exploitation Probability (EPSS)
Low risk3th percentile - higher than 3% of all known CVEs
Summary
The Windows installer deployed Npcap leaving its access restriction option at the insecure default value, so the driver was accessible to every local user of the host instead of being restricted to administrators only. A local user without administrative privileges could use the Npcap driver to capture the traffic reaching the host, which discloses information belonging both to the host and to other systems on the same network segment, and to send arbitrary raw packets on that segment.
Risk Assessment
Unauthorized users can sniff network traffic and send malicious packets, compromising confidentiality and integrity of data on the network.
Recommendation
Install the latest Npcap version that defaults to restricting driver access to administrators only, and review existing installations for proper configuration.
Original NVD description (English source)
The Windows installer deployed Npcap leaving its access restriction option at the insecure default value, so the driver was accessible to every local user of the host instead of being restricted to administrators only. A local user without administrative privileges could use the Npcap driver to capture the traffic reaching the host, which discloses information belonging both to the host and to other systems on the same network segment, and to send arbitrary raw packets on that segment.