CVE-2005-3500: The tnef_attachment function in tnef.c for Clam AntiVirus (ClamAV) before 0.87.1 allows remote attackers to ca

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MEDIUM 5.0DOWNGRADE

CVE-2005-3500 is a medium-severity flaw (CVSS 5.0) affecting clamav. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The tnef_attachment function in tnef.c for Clam AntiVirus (ClamAV) before 0.87.1 allows remote attackers to cause a denial of service (infinite loop and memory exhaustion) via a crafted value in a CAB file that causes ClamAV to repeatedly scan the same block.

Why this priority

EPSS top 10%: very likely to be exploited

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

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	4.0% (top 10%)
CISA exploited list	No
Published	2005-11-05
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: clam anti-virus

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

Am I affected?

Timeline

2005-11-05 11:02 UTCPublished CVE record published
2026-06-16 22:17 UTCUpdated Record last modified

clam anti-virus clamav DOWNGRADE

Affected: 0.15 · 0.20 · 0.21 · 0.22 · 0.23 · 0.24 · 0.51 · 0.52

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.15

1. Check installed version

apt-cache policy clamav || rpm -q clamav || clamav --version

2. No fixed release: DOWNGRADE to a release before 0.15 (Debian / Ubuntu)

apt-cache madison clamav sudo apt install clamav=<VERSION_BEFORE_0.15> sudo apt-mark hold clamav

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

dnf --showduplicates list clamav sudo dnf downgrade clamav-<VERSION_BEFORE_0.15> sudo dnf versionlock add clamav

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-2005-3500?

clamav: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2005-3500 being exploited?

CVE-2005-3500 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-2005-3500 affect?

CVE-2005-3500 affects clamav. Severity is medium (CVSS 5.0). The tnef_attachment function in tnef.c for Clam AntiVirus (ClamAV) before 0.87.1 allows remote attackers to cause a denial of service (infinite loop and memory exhaustion) via a crafted value in a CAB file that causes ClamAV to repeatedly s

How urgent is CVE-2005-3500?

Priority 40/100. EPSS top 10%: very likely to be exploited

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References

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