CVE-2021-33719

Name: CVE-2021-33719
Creator: NVD / NIST
Published: 2021-09-14T11:15:24.447+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 2.09%

Last modified Jun 17, 2026

CVE-2021-33719 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. A vulnerability has been identified in SIPROTEC 5 relays with CPU variants CP050 (All versions < V8.80), SIPROTEC 5 relays with CPU variants CP100 (All versions < V8.80), SIPROTEC 5 relays with CPU variants CP300 (All versions < V8.80). Specially crafted packets sent to port 4443/tcp could cause a Denial-of-Service condition or potential remote code execution.. EPSS estimates a 2.09% chance of exploitation in the next 30 days.

Description

A vulnerability has been identified in SIPROTEC 5 relays with CPU variants CP050 (All versions < V8.80), SIPROTEC 5 relays with CPU variants CP100 (All versions < V8.80), SIPROTEC 5 relays with CPU variants CP300 (All versions < V8.80). Specially crafted packets sent to port 4443/tcp could cause a Denial-of-Service condition or potential remote code execution.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

2.09%

79.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-120

Affected Software

Vendor	Product	Versions
Siemens	Siprotec 5 With Cpu Variant Cp050	< 8.80
Siemens	Siprotec 5 With Cpu Variant Cp100	< 8.80
Siemens	Siprotec 5 With Cpu Variant Cp300	< 8.80

References

https://cert-portal.siemens.com/productcert/pdf/ssa-847986.pdfPatch, Vendor Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-847986.pdfPatch, Vendor Advisory

Timeline

Published: Sep 14, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-33719?

How severe is CVE-2021-33719?

CVE-2021-33719 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 2.09% probability of exploitation in the next 30 days.

How do I fix CVE-2021-33719?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-33719?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST