Insufficient isolation in the Avast sandbox file virtualization layer on Windows allows a local, low-privileged attacker executing inside the sandbox to write arbitrary files outside sandbox containment and execute code on the host.
The sandbox virtualizes file system operations by intercepting write requests to protected system directories. However, the virtualization implementation fails to properly validate write targets in certain edge cases, allowing writes to bypass the virtualization redirection and reach the actual host file system in protected locations.
An attacker can exploit this to overwrite executable files, system libraries, or startup configurations with arbitrary content, leading to code execution with host privileges on subsequent system operations or reboot.
"}],"value":"Insufficient isolation in the Avast sandbox file virtualization layer on Windows allows a local, low-privileged attacker executing inside the sandbox to write arbitrary files outside sandbox containment and execute code on the host.\n\n\n\nThe sandbox virtualizes file system operations by intercepting write requests to protected system directories. However, the virtualization implementation fails to properly validate write targets in certain edge cases, allowing writes to bypass the virtualization redirection and reach the actual host file system in protected locations.\n\n\n\nAn attacker can exploit this to overwrite executable files, system libraries, or startup configurations with arbitrary content, leading to code execution with host privileges on subsequent system operations or reboot."}],"impacts":[{"descriptions":[{"lang":"en","value":"A local, low-privileged attacker executing in the Avast sandbox can write arbitrary files outside the sandbox boundary and execute code with host privileges."}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-434","description":"CWE-434: Unrestricted Upload of File with Dangerous Type","lang":"en","type":"CWE"},{"cweId":"CWE-653","description":"CWE-653: Improper Isolation or Compartmentalization","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-11-06T16:00:46.942Z","orgId":"dbd8429d-f261-4b1e-94cc-ae3132817e2e","shortName":"GEN"},"references":[{"name":"Gen Digital Security Advisories","tags":["vendor-advisory"],"url":"https://www.gendigital.com/us/en/contact-us/security-advisories/"},{"name":"Avast: how to update Avast Antivirus or Avast One","tags":["patch"],"url":"https://support.avast.com/en-us/article/Update-Antivirus"},{"name":"AVG: updating AVG AntiVirus","tags":["patch"],"url":"https://support.avg.com/SupportArticleView?l=en&urlname=Update-AVG-Antivirus"},{"name":"Norton: keep your Norton device security up to date","tags":["patch"],"url":"https://support.norton.com/sp/en/us/home/current/solutions/v20240108175512167"}],"solutions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"Gen Digital has released a fix in Avast, AVG, and Norton version 26.7 and later. The fix improves validation in the file virtualization layer to correctly identify protected directories and enforce write redirection in all code paths, preventing bypass of sandbox file isolation.
Upgrade to version 26.7 or later to remediate this issue.
"}],"value":"Gen Digital has released a fix in Avast, AVG, and Norton version 26.7 and later. The fix improves validation in the file virtualization layer to correctly identify protected directories and enforce write redirection in all code paths, preventing bypass of sandbox file isolation.\n\n\n\nUpgrade to version 26.7 or later to remediate this issue."}],"source":{"discovery":"EXTERNAL"},"title":"Avast sandbox escape via arbitrary file write in virtualized environment","x_generator":{"engine":"Vulnogram 1.0.5"}}},"cveMetadata":{"assignerOrgId":"dbd8429d-f261-4b1e-94cc-ae3132817e2e","assignerShortName":"GEN","cveId":"CVE-2026-80302","datePublished":"2026-11-06T16:00:46.942Z","dateReserved":"2026-08-26T08:11:54.260Z","dateUpdated":"2026-11-06T16:00:46.942Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-11-06 16:18:59","lastModifiedDate":"2026-11-06 16:18:59","problem_types":["CWE-434","CWE-653","CWE-434 CWE-434: Unrestricted Upload of File with Dangerous Type","CWE-653 CWE-653: Improper Isolation or Compartmentalization"],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"80302","Ordinal":"1","Title":"Avast sandbox escape via arbitrary file write in virtualized env","CVE":"CVE-2026-80302","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"80302","Ordinal":"1","NoteData":"Insufficient isolation in the Avast sandbox file virtualization layer on Windows allows a local, low-privileged attacker executing inside the sandbox to write arbitrary files outside sandbox containment and execute code on the host.\n\n\n\nThe sandbox virtualizes file system operations by intercepting write requests to protected system directories. However, the virtualization implementation fails to properly validate write targets in certain edge cases, allowing writes to bypass the virtualization redirection and reach the actual host file system in protected locations.\n\n\n\nAn attacker can exploit this to overwrite executable files, system libraries, or startup configurations with arbitrary content, leading to code execution with host privileges on subsequent system operations or reboot.","Type":"Description","Title":"Avast sandbox escape via arbitrary file write in virtualized env"}]}}}