CVE-2005-2920: Buffer overflow in libclamav/upx.c in Clam AntiVirus (ClamAV) before 0.87 allows remote attackers to execute a

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HIGH 7.5DOWNGRADE

CVE-2005-2920 is a high-severity flaw (CVSS 7.5) affecting clamav. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer overflow in libclamav/upx.c in Clam AntiVirus (ClamAV) before 0.87 allows remote attackers to execute arbitrary code via a crafted UPX packed executable.

Why this priority

High severity
EPSS top 5%: very likely to be exploited

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	8.2% (top 5%)
CISA exploited list	No
Published	2005-09-20
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

2005-09-20 23:03 UTCPublished CVE record published
2026-06-16 22:15 UTCUpdated Record last modified

clam anti-virus clamav DOWNGRADE

Affected: 0.70 · 0.71 · 0.72 · 0.73 · 0.74 · 0.75 · 0.75.1 · 0.80

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.70

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.70 (Debian / Ubuntu)

apt-cache madison clamav sudo apt install clamav=<VERSION_BEFORE_0.70> sudo apt-mark hold clamav

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

dnf --showduplicates list clamav sudo dnf downgrade clamav-<VERSION_BEFORE_0.70> 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-2005-2920?

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

Is CVE-2005-2920 being exploited?

CVE-2005-2920 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-2005-2920 affect?

CVE-2005-2920 affects clamav. Severity is high (CVSS 7.5). Buffer overflow in libclamav/upx.c in Clam AntiVirus (ClamAV) before 0.87 allows remote attackers to execute arbitrary code via a crafted UPX packed executable.

How urgent is CVE-2005-2920?

Priority 50/100. High severity; EPSS top 5%: very likely to be exploited

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References

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