How severe is CVE-2021-33542?

CVE-2021-33542 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-33542 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-33542?

CVE-2021-33542 primarily affects Phoenixcontact Config+. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-33542?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-33542 published?

CVE-2021-33542 was published on 2021-06-25 and last updated on 2026-06-17.

CVE-2021-33542

CVE-2021-33542 is a high-severity vulnerability in Phoenixcontact Config+ with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-824.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 5.1
EPSS exploit prediction: 2% (75th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-824
Affected product: Phoenixcontact Config+
Published: 2021-06-25
Last modified: 2026-06-17

Description

Phoenix Contact Classic Automation Worx Software Suite in Version 1.87 and below is affected by a remote code execution vulnerability. Manipulated PC Worx or Config+ projects could lead to a remote code execution when unallocated memory is freed because of incompletely initialized data. The attacker needs to get access to an original bus configuration file (*.bcp) to be able to manipulate data inside. After manipulation the attacker needs to exchange the original file by the manipulated one on the application programming workstation. Availability, integrity, or confidentiality of an application programming workstation might be compromised by attacks using these vulnerabilities. Automated systems in operation which were programmed with one of the above-mentioned products are not affected.

Frequently asked questions

What is CVE-2021-33542?: Phoenix Contact Classic Automation Worx Software Suite in Version 1.87 and below is affected by a remote code execution vulnerability. Manipulated PC Worx or Config+ projects could lead to a remote code execution when unallocated memory is freed because of incompletely initialized data. The attacker needs to get access to an original bus configuration file (*.bcp) to be able to manipulate data inside. After manipulation the attacker needs to exchange the original file by the manipulated one on the application programming workstation. Availability, integrity, or confidentiality of an application programming workstation might be compromised by attacks using these vulnerabilities. Automated systems in operation which were programmed with one of the above-mentioned products are not affected.
How severe is CVE-2021-33542?: CVE-2021-33542 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-33542 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-33542?: CVE-2021-33542 primarily affects Phoenixcontact Config+. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-33542?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-33542 published?: CVE-2021-33542 was published on 2021-06-25 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:phoenixcontact:config\+:*:*:*:*:*:*:*:*
cpe:2.3:a:phoenixcontact:pc_worx:*:*:*:*:*:*:*:*
cpe:2.3:a:phoenixcontact:pc_worx_express:*:*:*:*:*:*:*:*

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