CVE-2018-19666: The agent in OSSEC through 3.1.0 on Windows allows local users to gain NT AUTHORITY\SYSTEM access via Director

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HIGH 7.8UPGRADEUPGRADE

CVE-2018-19666 is a high-severity flaw (CVSS 7.8) affecting ossec, wazuh. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The agent in OSSEC through 3.1.0 on Windows allows local users to gain NT AUTHORITY\SYSTEM access via Directory Traversal by leveraging full access to the associated OSSEC server.

Why this priority

High severity
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.8% (top 44%)
CISA exploited list	No
Weakness	CWE-22
Published	2018-11-29
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: ossec · wazuh

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

Am I affected?

Timeline

2018-11-29 08:29 UTCPublished CVE record published
2026-06-17 01:49 UTCUpdated Record last modified

ossec ossec UPGRADE

Affected: <= 3.1.0

Fixed in: newer than 3.1.0

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 3.1.0 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade ossec

Note

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

wazuh wazuh UPGRADE

Affected: >= 1.0.0 and <= 2.1.1

Fixed in: newer than 2.1.1

Safe to downgrade to: a release before 1.0.0

1. Check installed version

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

2. UPGRADE to newer than 2.1.1 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade wazuh

Note

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

3. If no update is available yet, DOWNGRADE to a release before 1.0.0 (Debian / Ubuntu)

apt-cache madison wazuh sudo apt install wazuh=<VERSION_BEFORE_1.0.0> sudo apt-mark hold wazuh

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list wazuh sudo dnf downgrade wazuh-<VERSION_BEFORE_1.0.0> sudo dnf versionlock add wazuh

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-2018-19666?

ossec: upgrade to newer than 3.1.0; wazuh: upgrade to newer than 2.1.1. Exact commands for each OS are on this page.

Is CVE-2018-19666 being exploited?

CVE-2018-19666 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-2018-19666 affect?

CVE-2018-19666 affects ossec, wazuh. Severity is high (CVSS 7.8). The agent in OSSEC through 3.1.0 on Windows allows local users to gain NT AUTHORITY\SYSTEM access via Directory Traversal by leveraging full access to the associated OSSEC server.

How urgent is CVE-2018-19666?

Priority 46/100. High severity; Public exploit reference

Software pages

Windows vulnerabilities · Wazuh vulnerabilities

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CVE-2020-8448 MEDIUM 5.5 UPGRADE In OSSEC-HIDS 2.7 through 3.5.0, the server component responsible for log analysis (ossec-analysisd) is vulner
CVE-2020-8447 CRITICAL 9.8 UPGRADE In OSSEC-HIDS 2.7 through 3.5.0, the server component responsible for log analysis (ossec-analysisd) is vulner
CVE-2020-8446 MEDIUM 5.5 UPGRADE In OSSEC-HIDS 2.7 through 3.5.0, the server component responsible for log analysis (ossec-analysisd) is vulner
CVE-2020-8445 CRITICAL 9.8 UPGRADE In OSSEC-HIDS 2.7 through 3.5.0, the OS_CleanMSG function in ossec-analysisd doesn't remove or encode terminal

References

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