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VulnerabilityPublished

CVE-2026-80303: Gen Digital Avast Antivirus, Avast One, Avast Premium Security, Avast Ultimate · Integer Underflow

Affects Gen Digital Avast Antivirus, Avast One, Avast Premium Security, Avast UltimateSource CVE Database V5

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Not known to be exploited.

Data as of 6 Nov 2026, 16:20 UTC

Severity
High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 6 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
Gen DigitalAvast Antivirus, Avast One, Avast Premium Security, Avast UltimateAffected
  • <26.7
Fixed in–
Gen DigitalAVG Antivirus Free, AVG Internet Security, AVG UltimateAffected
  • <26.7
Fixed in–
Gen DigitalNorton Antivirus Plus, Norton 360 Standard, Norton 360 Deluxe, Norton 360 AdvancedAffected
  • <26.7
Fixed in–

AI-suggested

Users should monitor vendor advisories for updates. Until a fix is released, consider limiting exposure of the affected filtering interfaces to untrusted network traffic and avoid processing untrusted data through the affected components.

Description

CVE-2026-80303 is an integer underflow vulnerability in the Avast Windows Filtering Platform (WFP) stream parser on Windows. It allows denial of service by causing a system crash through improper length calculations during network stream processing. The vulnerability can be triggered remotely via network traffic or locally via crafted data, leading to kernel panic and system crash.

References

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