CVE-2026-82964
CVE-2026-82964 — Avast sandbox privilege escalation via unpreserved DACLs on virtualized files in aswSnx.sys
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…
Published Updated Sources: cvelistV5, GEN
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Unreported
no source claims exploitation
EPSS
0%
chance of exploitation in 30 days
CVSS base
8.8
HIGH
CISA SSVC assessment
Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.
Exploitation
PoC
none · proof-of-concept · active
Automatable
No
can an attacker script all four kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component
Affected scope
The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.
Vendors (1)
Products (3)
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 8.8 | CVSS 3.1 | HIGH | — | — | cvelistV5 |
Weakness & attack patterns
- CWE-281
- CWE-653
- CWE-862
Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.
- T1211Exploitation for Defensive Evasion
- T1542.002Pre-OS Boot: Component Firmware
- T1556Modify Authentication Process
References
6 on the record
- www.gendigital.com/us/en/contact-us/security-advisories/
vendor-advisory
- support.avast.com/en-us/article/Update-Antivirus
patch
- support.avg.com/SupportArticleView?l=en&urlname=Update-AVG-Antivirus
patch
- support.norton.com/sp/en/us/home/current/solutions/v20240108175512167
patch
- github.com/MSNightmare/PrettyPrague
exploit
- x.com/msnightmare2000/status/2094106041046765752
reference
Elsewhere on this site
- gen digitalevery CVE for this vendor
- CWE-281other pages naming this weakness
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.