CVE-2020-9342Network attack vector

Virus-detection bypass via malformed GZIP compression method

Published Feb 22, 2020 · Updated Aug 4, 2024

Virus-detection bypass in F-Secure Linux products before 17.0.605.474 allows attackers to pass crafted GZIP files unscanned. The AV parsing engine treats a failure caused by a manipulated GZIP Compression Method field as a clean result, although ordinary extraction still exposes the payload. Exploitation requires a crafted archive to reach Cloud Protection for Salesforce, Email and Server Security, or Internet GateKeeper for scanning; concealed malicious content can then pass a gateway or server-side scan without an alert.

CVSS severity5.5
Medium
EPSS probability1.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Virus-detection bypass in F-Secure Linux products before 17.0.605.474 allows attackers to pass crafted GZIP files unscanned. The AV parsing engine treats a failure caused by a manipulated GZIP Compression Method field as a clean result, although ordinary extraction still exposes the payload. Exploitation requires a crafted archive to reach Cloud Protection for Salesforce, Email and Server Security, or Internet GateKeeper for scanning; concealed malicious content can then pass a gateway or server-side scan without an alert.

The record

CVE
CVE-2020-9342
Published
Feb 22, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-436, T1027.015
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 22, 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

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-436Interpretation Conflict
T1027.015Obfuscated Files or Information: Compression

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

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Your stack

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