CVE-2005-3374: Multiple interpretation error in F-Prot 3.16c allows remote attackers to bypass virus scanning via a file such

Routine

MEDIUM 5.1DOWNGRADE

CVE-2005-3374 is a medium-severity flaw (CVSS 5.1) affecting f-prot antivirus. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Multiple interpretation error in F-Prot 3.16c allows remote attackers to bypass virus scanning via a file such as BAT, HTML, and EML with an "MZ" magic byte sequence which is normally associated with EXE, which causes the file to be treated as a safe type that could still be executed as a dangerous file type by applications on the end system, as demonstrated by a "triple headed" program that contains EXE, EML, and HTML content, aka the "magic byt

Why this priority

No elevated risk signals yet

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.1 (Medium)
EPSS exploit chance	1.4% (top 28%)
CISA exploited list	No
Published	2005-10-30
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: frisk software

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2005-10-30 14:34 UTCPublished CVE record published
2026-06-16 22:16 UTCUpdated Record last modified

frisk software f-prot antivirus DOWNGRADE

Affected: 3.16c

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.16c

1. Check installed version

apt-cache policy f-prot-antivirus || rpm -q f-prot-antivirus || f-prot-antivirus --version

2. No fixed release: DOWNGRADE to a release before 3.16c (Debian / Ubuntu)

apt-cache madison f-prot-antivirus sudo apt install f-prot-antivirus=<VERSION_BEFORE_3.16c> sudo apt-mark hold f-prot-antivirus

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list f-prot-antivirus sudo dnf downgrade f-prot-antivirus-<VERSION_BEFORE_3.16c> sudo dnf versionlock add f-prot-antivirus

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2005-3374?

f-prot antivirus: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2005-3374 being exploited?

CVE-2005-3374 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2005-3374 affect?

CVE-2005-3374 affects f-prot antivirus. Severity is medium (CVSS 5.1). Multiple interpretation error in F-Prot 3.16c allows remote attackers to bypass virus scanning via a file such as BAT, HTML, and EML with an "MZ" magic byte sequence which is normally associated with EXE, which causes the file to be treated

How urgent is CVE-2005-3374?

Priority 36/100. No elevated risk signals yet.

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References

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