Is CVE-2021-33719 actively exploited?

No active exploitation of CVE-2021-33719 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-33719 be exploited remotely?

Yes. CVE-2021-33719 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-33719?

CVE-2021-33719 has a CVSS score of 9.8 (CRITICAL).

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CRITICAL

CVE-2021-33719

CWE-120Published: September 14, 2021· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2021-33719 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.