CVE-2020-9399

The Avast AV parsing engine allows virus-detection bypass via a crafted ZIP archive. This affects versions before 12 definitions 200114-0 of Antivirus Pro, Antivirus Pro Plus, and Antivirus for Linux.

Published: 2020-02-28 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-9399 is rated Moderate Risk (44.8/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.14%). EPSS rose +1.03% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-9399

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.11% 1.14% +1.03%
2 2025-11-21 0.19% 0.11% -0.08%
3 2025-11-18 — 0.19% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-9399

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 1.8 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2020-9399

Affected software / configurations for CVE-2020-9399

Vendor Product Version Raw CPE
avast antivirus_for_linux < 12.0 cpe:2.3:a:avast:antivirus_for_linux:*:*:*:*:*:*:*:*
avast antivirus_pro < 12.0 cpe:2.3:a:avast:antivirus_pro:*:*:*:*:*:*:*:*
avast antivirus_pro_plus < 12.0 cpe:2.3:a:avast:antivirus_pro_plus:*:*:*:*:*:*:*:*

References for CVE-2020-9399

cvelogic Threat Intelligence