CVE-2020-13559: A denial-of-service vulnerability exists in the traffic-logging functionality of FreyrSCADA IEC-60879-5-104 Se

This week

HIGH 7.5REMOTEDOWNGRADE

CVE-2020-13559 is a high-severity flaw (CVSS 7.5) affecting iec-60879-5-104 server simulator. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A denial-of-service vulnerability exists in the traffic-logging functionality of FreyrSCADA IEC-60879-5-104 Server Simulator 21.04.028. A specially crafted packet can lead to denial of service. An attacker can send a malicious packet to trigger this vulnerability.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.3% (top 29%)
CISA exploited list	No
Weakness	CWE-1024, CWE-697
Published	2021-01-11
Last modified	2026-06-17

Publisher (CNA): Talos · Vendor: freyrscada

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

Am I affected?

Timeline

2021-01-11 19:15 UTCPublished CVE record published
2026-06-17 02:53 UTCUpdated Record last modified

freyrscada iec-60879-5-104 server simulator DOWNGRADE

Affected: 21.04.028

Fixed in: no fixed release known

Safe to downgrade to: a release before 21.04.028

1. Check installed version

apt-cache policy iec-60879-5-104-server-simulator || rpm -q iec-60879-5-104-server-simulator || iec-60879-5-104-server-simulator --version

2. No fixed release: DOWNGRADE to a release before 21.04.028 (Debian / Ubuntu)

apt-cache madison iec-60879-5-104-server-simulator sudo apt install iec-60879-5-104-server-simulator=<VERSION_BEFORE_21.04.028> sudo apt-mark hold iec-60879-5-104-server-simulator

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

dnf --showduplicates list iec-60879-5-104-server-simulator sudo dnf downgrade iec-60879-5-104-server-simulator-<VERSION_BEFORE_21.04.028> sudo dnf versionlock add iec-60879-5-104-server-simulator

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-2020-13559?

iec-60879-5-104 server simulator: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-13559 being exploited?

CVE-2020-13559 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-2020-13559 affect?

CVE-2020-13559 affects iec-60879-5-104 server simulator. Severity is high (CVSS 7.5). A denial-of-service vulnerability exists in the traffic-logging functionality of FreyrSCADA IEC-60879-5-104 Server Simulator 21.04.028. A specially crafted packet can lead to denial of service. An attacker can send a malicious packet to tri

How urgent is CVE-2020-13559?

Priority 54/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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