CVE-2020-18731: A segmentation violation in the Iec104_Deal_FirmUpdate function of IEC104 v1.0 allows attackers to cause a den

This week

HIGH 7.5REMOTEDOWNGRADE

CVE-2020-18731 is a high-severity flaw (CVSS 7.5) affecting iec104. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A segmentation violation in the Iec104_Deal_FirmUpdate function of IEC104 v1.0 allows attackers to cause a denial of service (DOS).

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	1.4% (top 27%)
CISA exploited list	No
Weakness	CWE-476
Published	2021-08-23
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: iec104 project

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

Am I affected?

Timeline

2021-08-23 21:15 UTCPublished CVE record published
2026-06-17 02:59 UTCUpdated Record last modified

iec104 project iec104 DOWNGRADE

Affected: 1.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0

1. Check installed version

apt-cache policy iec104 || rpm -q iec104 || iec104 --version

2. No fixed release: DOWNGRADE to a release before 1.0 (Debian / Ubuntu)

apt-cache madison iec104 sudo apt install iec104=<VERSION_BEFORE_1.0> sudo apt-mark hold iec104

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

dnf --showduplicates list iec104 sudo dnf downgrade iec104-<VERSION_BEFORE_1.0> sudo dnf versionlock add iec104

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-2020-18731?

iec104: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-18731 being exploited?

CVE-2020-18731 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-2020-18731 affect?

CVE-2020-18731 affects iec104. Severity is high (CVSS 7.5). A segmentation violation in the Iec104_Deal_FirmUpdate function of IEC104 v1.0 allows attackers to cause a denial of service (DOS).

How urgent is CVE-2020-18731?

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

Related CVEs

CVE-2025-63929 HIGH 7.5 UPGRADE A null pointer dereference vulnerability exists in airpig2011 IEC104 thru Commit be6d841 (2019-07-08)
CVE-2025-63927 MEDIUM 4.0 UPGRADE A heap-use-after-free vulnerability exists in airpig2011 IEC104 thru Commit be6d841 (2019-07-08)
CVE-2020-20486 HIGH 7.5 DOWNGRADE IEC104 v1.0 contains a stack-buffer overflow in the parameter Iec10x_Sta_Addr.
CVE-2020-18730 HIGH 7.5 DOWNGRADE A segmentation violation in the Iec104_Deal_I function of IEC104 v1.0 allows attackers to cause a denial of se

References

← Back to latest CVEs