CVE-2018-6940: A /shell?cmd= XSS issue exists in the HTTPD component of NAT32 v2.2 Build 22284 devices that can be exploited

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MEDIUM 6.1DOWNGRADE

CVE-2018-6940 is a medium-severity flaw (CVSS 6.1) affecting nat32. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A /shell?cmd= XSS issue exists in the HTTPD component of NAT32 v2.2 Build 22284 devices that can be exploited for Remote Code Execution in conjunction with CSRF.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	2.8% (top 14%)
CISA exploited list	No
Weakness	CWE-79, CWE-352
Published	2018-02-20
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: nat32

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

Am I affected?

Timeline

2018-02-20 15:29 UTCPublished CVE record published
2026-06-17 02:02 UTCUpdated Record last modified

nat32 nat32 DOWNGRADE

Affected: 2.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.2

1. Check installed version

apt-cache policy nat32 || rpm -q nat32 || nat32 --version

2. No fixed release: DOWNGRADE to a release before 2.2 (Debian / Ubuntu)

apt-cache madison nat32 sudo apt install nat32=<VERSION_BEFORE_2.2> sudo apt-mark hold nat32

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

dnf --showduplicates list nat32 sudo dnf downgrade nat32-<VERSION_BEFORE_2.2> sudo dnf versionlock add nat32

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.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: NAT32 2.2 Build 22284 - Remote Command Execution

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-2018-6940?

nat32: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-6940 being exploited?

CVE-2018-6940 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-2018-6940 affect?

CVE-2018-6940 affects nat32. Severity is medium (CVSS 6.1). A /shell?cmd= XSS issue exists in the HTTPD component of NAT32 v2.2 Build 22284 devices that can be exploited for Remote Code Execution in conjunction with CSRF.

How urgent is CVE-2018-6940?

Priority 48/100. Public exploit reference

Software pages

Apache HTTP Server vulnerabilities

Related CVEs

CVE-2018-6941 HIGH 8.8 DOWNGRADE A /shell?cmd= CSRF issue exists in the HTTPD component of NAT32 v2.2 Build 22284 devices that can be exploited

References

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