CVE-2022-31803: In CODESYS Gateway Server V2 an insufficient check for the activity of TCP client connections allows an unauth

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MEDIUM 5.3REMOTEUPGRADE

CVE-2022-31803 is a medium-severity flaw (CVSS 5.3) affecting gateway. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In CODESYS Gateway Server V2 an insufficient check for the activity of TCP client connections allows an unauthenticated attacker to consume all available TCP connections and prevent legitimate users or clients from establishing a new connection to the CODESYS Gateway Server V2. Existing connections are not affected and therefore remain intact.

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.2% (top 33%)
CISA exploited list	No
Weakness	CWE-400
Published	2022-06-24
Last modified	2026-06-17

Publisher (CNA): CERT VDE · Vendor: codesys

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

Am I affected?

Timeline

2022-06-24 08:15 UTCPublished CVE record published
2026-06-17 04:46 UTCUpdated Record last modified

codesys gateway UPGRADE

Affected: >= 2.0 and < 2.3.9.38

Fixed in: 2.3.9.38

Safe to downgrade to: a release before 2.0

1. Check installed version

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

2. UPGRADE to 2.3.9.38 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade gateway

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 2.0 (Debian / Ubuntu)

apt-cache madison gateway sudo apt install gateway=<VERSION_BEFORE_2.0> sudo apt-mark hold gateway

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

dnf --showduplicates list gateway sudo dnf downgrade gateway-<VERSION_BEFORE_2.0> sudo dnf versionlock add gateway

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-2022-31803?

gateway: upgrade to 2.3.9.38. Exact commands for each OS are on this page.

Is CVE-2022-31803 being exploited?

CVE-2022-31803 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-2022-31803 affect?

CVE-2022-31803 affects gateway. Severity is medium (CVSS 5.3). In CODESYS Gateway Server V2 an insufficient check for the activity of TCP client connections allows an unauthenticated attacker to consume all available TCP connections and prevent legitimate users or clients from establishing a new connec

How urgent is CVE-2022-31803?

Priority 40/100. Remotely exploitable, no login, no user action

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References

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