CVE-2026-82964Avast sandbox privilege escalation via unpreserved DACLs on virtualized files in aswSnx.sys
Updated under an hour ago ()
Does this affect you?
It affects Gen Digital Avast Free Antivirus, Avast One, Avast Premium Security, Avast Ultimate, Avast Business Security and 2 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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. When 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. The 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.
- CVSS
- 8.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- Weakness (CWE)
- CWE-281, CWE-653, CWE-862
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GEN
- NVD analysis
- Awaiting Analysis
- Record last updated
- Sep 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Gen Digital Avast Free Antivirus, Avast One, Avast Premium Security, Avast Ultimate, Avast Business Security gen_digital:avast_free_antivirus_avast_one_avast_premium_security_avast_ultimate_avast_business_security (from the name) | before 26.8 | CNA record |
Gen Digital AVG Antivirus Free, AVG Internet Security, AVG Ultimate gen_digital:avg_antivirus_free_avg_internet_security_avg_ultimate (from the name) | before 26.8 | CNA record |
Gen Digital Norton Antivirus Plus, Norton 360 Standard, Norton 360 Deluxe, Norton 360 Advanced gen_digital:norton_antivirus_plus_norton_360_standard_norton_360_deluxe_norton_360_advanced (from the name) | before 26.8 | CNA record |
References
- https://www.gendigital.com/us/en/contact-us/security-advisories/vendor-advisory
- https://support.avast.com/en-us/article/Update-Antiviruspatch
- https://support.avg.com/SupportArticleView?l=en&urlname=Update-AVG-Antiviruspatch
- https://support.norton.com/sp/en/us/home/current/solutions/v20240108175512167patch
- https://github.com/MSNightmare/PrettyPragueexploit
- https://x.com/msnightmare2000/status/2094106041046765752
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.