CVE-2007-2846: Heap-based buffer overflow in the SIS unpacker in avast! Anti-Virus Managed Client before 4.7.700 allows user-

Q: How do I fix CVE-2007-2846?

avast\! antivirus: downgrade or apply the listed mitigation; avast\! antivirus: upgrade to newer than 4.7.652. Exact commands for each OS are on this page.

Q: Is CVE-2007-2846 being exploited?

CVE-2007-2846 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2007-2846 affect?

CVE-2007-2846 affects avast\! antivirus, avast\! antivirus. Severity is high (CVSS 9.3). Heap-based buffer overflow in the SIS unpacker in avast! Anti-Virus Managed Client before 4.7.700 allows user-assisted remote attackers to execute arbitrary code via a crafted SIS archive, resulting from an "integer cast around."

Q: How urgent is CVE-2007-2846?

Priority 56/100. Critical severity; EPSS top 5%: very likely to be exploited

This month

HIGH 9.3DOWNGRADEUPGRADE

CVE-2007-2846 is a high-severity flaw (CVSS 9.3) affecting avast\! antivirus, avast\! antivirus. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Heap-based buffer overflow in the SIS unpacker in avast! Anti-Virus Managed Client before 4.7.700 allows user-assisted remote attackers to execute arbitrary code via a crafted SIS archive, resulting from an "integer cast around."

Why this priority

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

A fixed release or distro patch exists.

Risk facts

CVSS score	9.3 (High)
EPSS exploit chance	7.7% (top 5%)
CISA exploited list	No
Weakness	CWE-119
Published	2007-05-24
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: avas\!t · avast\!

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

Am I affected?

Timeline

2007-05-24 18:30 UTCPublished CVE record published
2026-06-16 22:40 UTCUpdated Record last modified

avas\!t avast\! antivirus DOWNGRADE

Affected: 4.6.394

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.6.394

1. Check installed version

apt-cache policy avast-antivirus || rpm -q avast-antivirus || avast-antivirus --version

2. No fixed release: DOWNGRADE to a release before 4.6.394 (Debian / Ubuntu)

apt-cache madison avast-antivirus sudo apt install avast-antivirus=<VERSION_BEFORE_4.6.394> sudo apt-mark hold avast-antivirus

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

dnf --showduplicates list avast-antivirus sudo dnf downgrade avast-antivirus-<VERSION_BEFORE_4.6.394> sudo dnf versionlock add avast-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.

avast\! avast\! antivirus UPGRADE

Affected: <= 4.7.652

Fixed in: newer than 4.7.652

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy avast-antivirus || rpm -q avast-antivirus || avast-antivirus --version

2. UPGRADE to newer than 4.7.652 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade avast-antivirus

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade avast-antivirus

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2007-2846?

avast\! antivirus: downgrade or apply the listed mitigation; avast\! antivirus: upgrade to newer than 4.7.652. Exact commands for each OS are on this page.

Is CVE-2007-2846 being exploited?

CVE-2007-2846 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-2007-2846 affect?

CVE-2007-2846 affects avast\! antivirus, avast\! antivirus. Severity is high (CVSS 9.3). Heap-based buffer overflow in the SIS unpacker in avast! Anti-Virus Managed Client before 4.7.700 allows user-assisted remote attackers to execute arbitrary code via a crafted SIS archive, resulting from an "integer cast around."

How urgent is CVE-2007-2846?

Priority 56/100. Critical severity; EPSS top 5%: very likely to be exploited

References

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