{"id":"CVE-2026-82964","title":"Improper preservation of permissions in the Avast sandbox minifilter driver (aswSnx.sys) on Windows allows a local, low-privileged attacker executing inside the sandbox to escape file isolation and escalate to SYSTEM.\n\n\n\nWhen the sandbox…","summary":"Improper preservation of permissions in the Avast sandbox minifilter driver (aswSnx.sys) on Windows allows a local, low-privileged attacker executing inside the sandbox to escape file isolation and escalate to SYSTEM.\n\n\n\nWhen the sandbox…","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","cwe":["CWE-281","CWE-653","CWE-862"],"vendor":"Gen Digital","product":"Avast Free Antivirus, Avast One, Avast Premium Security, Avast Ultimate, Avast Business Security","affected":["avast_free_antivirus_avast_one_avast_premium_security_avast_ultimate_avast_business_security < 26.8","avg_antivirus_free_avg_internet_security_avg_ultimate < 26.8","norton_antivirus_plus_norton_360_standard_norton_360_deluxe_norton_360_advanced < 26.8"],"published":"2026-09-16","updated":"2026-09-17","sourceUpdated":"2026-09-17T19:17:05.013","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-82964","references":[{"url":"https://github.com/MSNightmare/PrettyPrague","label":"security@nortonlifelock.com"},{"url":"https://support.avast.com/en-us/article/Update-Antivirus","label":"security@nortonlifelock.com"},{"url":"https://support.avg.com/SupportArticleView?l=en&urlname=Update-AVG-Antivirus","label":"security@nortonlifelock.com"},{"url":"https://support.norton.com/sp/en/us/home/current/solutions/v20240108175512167","label":"security@nortonlifelock.com"},{"url":"https://www.gendigital.com/us/en/contact-us/security-advisories/","label":"security@nortonlifelock.com"},{"url":"https://x.com/msnightmare2000/status/2094106041046765752","label":"security@nortonlifelock.com"}],"tags":["nvd","cve.org","exploit-available"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"total","timestamp":"2026-09-17T18:41:32.262077Z"},"ingestedAt":"2026-09-16T14:57:28.037Z","epss":0.00136,"epssPercentile":0.03433,"slug":"CVE-2026-82964","body":"## Overview\n\nImproper preservation of permissions in the Avast sandbox minifilter driver (aswSnx.sys) on Windows allows a local, low-privileged attacker executing inside the sandbox to escape file isolation and escalate to SYSTEM.\n\n\n\nWhen the sandbox virtualizes a file it copies the original security descriptor, but the driver opened the virtualization target object with GENERIC_WRITE and FILE_WRITE_ATTRIBUTES only, omitting WRITE_DAC. Every attempt to apply the original DACL therefore failed, and the failure was discarded silently, leaving virtualized copies of sensitive files with permissive permissions. Because the IRP_MJ_CREATE callback additionally did not strip WRITE_DAC for sensitive directories, a sandboxed process could rewrite the security descriptor of a virtualized object, read the virtualized copy of the SAM database, extract local NTLM password hashes and execute code as SYSTEM.\n\n\n\nThe absence of an IRP_MJ_SET_SECURITY callback in the driver's operation registration table is a related defense-in-depth gap, but it is not the control that prevents this attack.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":60,"depthScoreParts":{"impact":48.4,"likelihood":0,"exploitation":12,"ransomware":0},"changes":[{"seq":206509,"id":"CVE-2026-82964","ts":1789673241276,"field":"exploit_available","old":"false","new":"true"}]}