CVE-2020-20118: Buffer Overflow vulnerability in Avast AntiVirus before v.19.7 allows a local attacker to cause a denial of se

Q: How do I fix CVE-2020-20118?

antivirus: upgrade to 19.7. Exact commands for each OS are on this page.

Q: Is CVE-2020-20118 being exploited?

CVE-2020-20118 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-2020-20118 affect?

CVE-2020-20118 affects antivirus. Severity is medium (CVSS 5.5). Buffer Overflow vulnerability in Avast AntiVirus before v.19.7 allows a local attacker to cause a denial of service via a crafted request to the aswSnx.sys driver.

Q: How urgent is CVE-2020-20118?

Priority 21/100. No elevated risk signals yet.

Routine

MEDIUM 5.5UPGRADE

CVE-2020-20118 is a medium-severity flaw (CVSS 5.5) affecting antivirus. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer Overflow vulnerability in Avast AntiVirus before v.19.7 allows a local attacker to cause a denial of service via a crafted request to the aswSnx.sys driver.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 94%)
CISA exploited list	No
Weakness	CWE-120
Published	2023-07-11
Last modified	2026-07-09

Publisher (CNA): MITRE · Vendor: avast

Last updated 2026-07-09 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-07-11 14:15 UTCPublished CVE record published
2026-07-09 00:16 UTCUpdated Record last modified

avast antivirus UPGRADE

Affected: < 19.7

Fixed in: 19.7

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 19.7 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade 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-2020-20118?

antivirus: upgrade to 19.7. Exact commands for each OS are on this page.

Is CVE-2020-20118 being exploited?

CVE-2020-20118 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-2020-20118 affect?

CVE-2020-20118 affects antivirus. Severity is medium (CVSS 5.5). Buffer Overflow vulnerability in Avast AntiVirus before v.19.7 allows a local attacker to cause a denial of service via a crafted request to the aswSnx.sys driver.

How urgent is CVE-2020-20118?

Priority 21/100. No elevated risk signals yet.

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References

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