CVE-2020-9320

Malware detection bypass via malformed ISO parsing

Published Feb 20, 2020 · Updated Aug 4, 2024

Antivirus bypass in Avira AV Engine before 8.3.54.138 allows attackers to conceal malicious files inside a crafted ISO archive. The ISO container parser accepts a specifically manipulated archive but skips inspection of its contents, causing endpoints to ignore the container and gateways to pass it as clean. An attacker must deliver the archive for scanning and rely on a recipient or downstream system to open its hidden payload; Avira disputes that the flaw exists.

CVSS severity5.5
Medium
EPSS probability2.88%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Antivirus bypass in Avira AV Engine before 8.3.54.138 allows attackers to conceal malicious files inside a crafted ISO archive. The ISO container parser accepts a specifically manipulated archive but skips inspection of its contents, causing endpoints to ignore the container and gateways to pass it as clean. An attacker must deliver the archive for scanning and rely on a recipient or downstream system to open its hidden payload; Avira disputes that the flaw exists.

The record

CVE
CVE-2020-9320
Published
Feb 20, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-434, T1027
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 20, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1027Obfuscated Files or Information

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo