CVE-2020-13657

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-06-29 · updated 2026-06-17

Description

An elevation of privilege vulnerability exists in Avast Free Antivirus and AVG AntiVirus Free before 20.4 due to improperly handling hard links. The vulnerability allows local users to take control of arbitrary files.

Affected products

Avast/Avg Antivirus: before 20.4 — fixed in 20.4
Avast Free Antivirus: before 20.4 — fixed in 20.4

How to fix

Upgrade to a fixed version: Avast/Avg Antivirus 20.4; Avast Free Antivirus 20.4. Check the vendor advisory for mitigations.

References

https://forum.avast.com/index.php?topic=232423.0
https://forum.avast.com/index.php?topic=234638.0
https://forum.avast.com/index.php?topic=232423.0
https://forum.avast.com/index.php?topic=234638.0

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