CVE-2018-15731: An issue was discovered in STOPzilla AntiMalware 6.5.2.59

Routine

MEDIUM 5.5DOWNGRADE

CVE-2018-15731 is a medium-severity flaw (CVSS 5.5) affecting antimalware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in STOPzilla AntiMalware 6.5.2.59. The driver file szkg64.sys contains a Denial of Service vulnerability due to not validating the output buffer address value from IOCtl 0x8000205B.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.4% (top 62%)
CISA exploited list	No
Weakness	CWE-20
Published	2019-06-21
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: stopzilla

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2019-06-21 15:15 UTCPublished CVE record published
2026-06-17 01:43 UTCUpdated Record last modified

stopzilla antimalware DOWNGRADE

Affected: 6.5.2.59

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.5.2.59

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 6.5.2.59 (Debian / Ubuntu)

apt-cache madison antimalware sudo apt install antimalware=<VERSION_BEFORE_6.5.2.59> sudo apt-mark hold antimalware

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

dnf --showduplicates list antimalware sudo dnf downgrade antimalware-<VERSION_BEFORE_6.5.2.59> sudo dnf versionlock add antimalware

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-2018-15731?

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

Is CVE-2018-15731 being exploited?

CVE-2018-15731 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-2018-15731 affect?

CVE-2018-15731 affects antimalware. Severity is medium (CVSS 5.5). An issue was discovered in STOPzilla AntiMalware 6.5.2.59. The driver file szkg64.sys contains a Denial of Service vulnerability due to not validating the output buffer address value from IOCtl 0x8000205B.

How urgent is CVE-2018-15731?

Priority 34/100. Public exploit reference

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References

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