CVE-2026-80303

Full vulnerability record from the local CVENow database.

Description

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.

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

[email protected]

Published

2026-11-06 16:18:59.170000

Last modified

2026-11-06 16:18:59.170000

View original CVE JSON

{
  "id": "CVE-2026-80303",
  "sourceIdentifier": "[email protected]",
  "published": "2026-11-06T16:18:59.170",
  "lastModified": "2026-11-06T16:18:59.170",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "An integer underflow vulnerability in the Avast Windows Filtering Platform (WFP) stream parser on Windows allows denial of service by causing a system crash.\n\n\n\nThe 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.\n\n\n\nThe 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."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Gen Digital",
          "product": "Avast Antivirus, Avast One, Avast Premium Security, Avast Ultimate",
          "defaultStatus": "affected",
          "platforms": [
            "Windows"
          ],
          "versions": [
            {
              "version": "0",
              "lessThan": "26.7",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Gen Digital",
          "product": "AVG Antivirus Free, AVG Internet Security, AVG Ultimate",
          "defaultStatus": "affected",
          "platforms": [
            "Windows"
          ],
          "versions": [
            {
              "version": "0",
              "lessThan": "26.7",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Gen Digital",
          "product": "Norton Antivirus Plus, Norton 360 Standard, Norton 360 Deluxe, Norton 360 Advanced",
          "defaultStatus": "affected",
          "platforms": [
            "Windows"
          ],
          "versions": [
            {
              "version": "0",
              "lessThan": "26.7",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-191"
        },
        {
          "lang": "en",
          "value": "CWE-248"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://support.avast.com/en-us/article/Update-Antivirus",
      "source": "[email protected]"
    },
    {
      "url": "https://support.avg.com/SupportArticleView?l=en&urlname=Update-AVG-Antivirus",
      "source": "[email protected]"
    },
    {
      "url": "https://support.norton.com/sp/en/us/home/current/solutions/v20240108175512167",
      "source": "[email protected]"
    },
    {
      "url": "https://www.gendigital.com/us/en/contact-us/security-advisories/",
      "source": "[email protected]"
    }
  ]
}