Avast sandbox escape via arbitrary file write in virtualized environment

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-80302
StatePUBLISHED
AssignerGEN
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-06 16:18:59 UTC
Updated2026-11-06 16:18:59 UTC
DescriptionInsufficient 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.

Risk And Classification

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Gen Digital Avast Antivirus Avast One Avast Premium Security Avast Ultimate affected 26.7 custom Windows
CNA Gen Digital AVG Antivirus Free AVG Internet Security AVG Ultimate affected 26.7 custom Windows
CNA Gen Digital Norton Antivirus Plus Norton 360 Standard Norton 360 Deluxe Norton 360 Advanced affected 26.7 custom Windows

References

ReferenceSourceLinkTags
support.avg.com/SupportArticleView [email protected] support.avg.com
www.gendigital.com/us/en/contact-us/security-advisories [email protected] www.gendigital.com
support.avast.com/en-us/article/Update-Antivirus [email protected] support.avast.com
support.norton.com/sp/en/us/home/current/solutions/v20240108175512167 [email protected] support.norton.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Teng Zheng Wang by VulnGuard Labs (en)

Additional Advisory Data

Solutions

CNA: 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.

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