How severe is CVE-2020-9399?

CVE-2020-9399 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2020-9399 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-9399?

CVE-2020-9399 primarily affects Avast Antivirus For Linux. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-9399?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-9399 published?

CVE-2020-9399 was published on 2020-02-28 and last updated on 2026-06-17.

CVE-2020-9399

CVE-2020-9399 is a medium-severity vulnerability in Avast Antivirus For Linux with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-436.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
CVSS v2: 4.3
EPSS exploit prediction: 1% (63rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-436
Affected product: Avast Antivirus For Linux
Published: 2020-02-28
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2020-9399?: CVE-2020-9399 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2020-9399 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-9399?: CVE-2020-9399 primarily affects Avast Antivirus For Linux. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-9399?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-9399 published?: CVE-2020-9399 was published on 2020-02-28 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:avast:antivirus_for_linux:*:*:*:*:*:*:*:*
cpe:2.3:a:avast:antivirus_pro:*:*:*:*:*:*:*:*
cpe:2.3:a:avast:antivirus_pro_plus:*:*:*:*:*:*:*:*

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