Cyber Resilience

CVE-2021-45335

HighPublic PoC

Published: 27 December 2021

Published
27 December 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS Score 0.0018 39.0th percentile
Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-45335 is a high-severity Incorrect Default Permissions (CWE-276) vulnerability in Avast Antivirus. Its CVSS base score is 8.8 (High).

Operationally, ranked at the 39.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

Sandbox component in Avast Antivirus prior to 20.4 has an insecure permission which could be abused by local user to control the outcome of scans, and therefore evade detection or delete arbitrary system files.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

avast
antivirus
≤ 20.4

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-276

Access control policy can specify and enforce secure default permissions for resources.

addresses: CWE-276

Guides setting of default permissions to the minimum required level.

addresses: CWE-276

Establishes requirements for appropriate default permissions on system resources as part of configuration management.

addresses: CWE-276

Baseline establishment and updates on install/upgrade ensure correct default permissions rather than insecure ones.

addresses: CWE-276

Requiring the most restrictive settings instead of defaults prevents incorrect default permissions on resources.

addresses: CWE-276

Requires documented processes that include setting and maintaining correct default permissions for configuration items.

addresses: CWE-276

Requires addressing secure default permissions in physical and environmental protection controls.

addresses: CWE-276

Tailoring explicitly overrides or scopes default permission assignments in the baseline to match the system's actual risk and operational needs.

References