CVE-2026-80303 · Other
NO FIX YET
An integer underflow in the Avast Windows Filtering Platform stream parser lets crafted network traffic or local input wrap a length value. The result is a kernel panic that crashes the Windows machine.
first public Nov 6, 2026 · 1 source
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Windows machines running Avast security software with its Windows Filtering Platform callout driver are the ones described as exposed. Network traffic to filtered ports can trigger it remotely, and local crafted input can trigger it too. Systems without the Avast driver are not described as affected. The sources do not give affected versions.
Not affected if no-avast-installed
Who cares avast, kernel-driver, windows
No fix yet, per the sources.
An integer underflow vulnerability in the Avast Windows Filtering Platform (WFP) stream parser on Windows allows denial of service by causing a system crash.
The WFP callout driver processes network stream data and computes length values for packet fragment reassembly. The length calculation does not properly validate input stream sizes against expected boundaries. When processing specially crafted input, the length computation underflows, resulting in allocation or buffer access with an extremely large wrapped-around size value.
The underflow can be triggered remotely via network traffic destined for the filtered port, or locally via crafted data provided to the filtering interface. The resulting memory allocation failure or out-of-bounds access causes a kernel panic and system crash.
NVD data is provided by NIST and is public domain. Posts quoted belong to their authors.
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