How severe is CVE-2021-37172?

CVE-2021-37172 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2021-37172 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-37172?

CVE-2021-37172 primarily affects Siemens Simatic S7-1200 Cpu Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-37172?

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-2021-37172 published?

CVE-2021-37172 was published on 2021-08-10 and last updated on 2026-06-17.

CVE-2021-37172

CVE-2021-37172 is a high-severity vulnerability in Siemens Simatic S7-1200 Cpu Firmware with a CVSS 3.x base score of 7.5. 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-287.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (56th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Siemens Simatic S7-1200 Cpu Firmware
Published: 2021-08-10
Last modified: 2026-06-17

Description

A vulnerability has been identified in SIMATIC S7-1200 CPU family (incl. SIPLUS variants) (V4.5.0). Affected devices fail to authenticate against configured passwords when provisioned using TIA Portal V13. This could allow an attacker using TIA Portal V13 or later versions to bypass authentication and download arbitrary programs to the PLC. The vulnerability does not occur when TIA Portal V13 SP1 or any later version was used to provision the device.

Frequently asked questions

What is CVE-2021-37172?: A vulnerability has been identified in SIMATIC S7-1200 CPU family (incl. SIPLUS variants) (V4.5.0). Affected devices fail to authenticate against configured passwords when provisioned using TIA Portal V13. This could allow an attacker using TIA Portal V13 or later versions to bypass authentication and download arbitrary programs to the PLC. The vulnerability does not occur when TIA Portal V13 SP1 or any later version was used to provision the device.
How severe is CVE-2021-37172?: CVE-2021-37172 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2021-37172 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-37172?: CVE-2021-37172 primarily affects Siemens Simatic S7-1200 Cpu Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-37172?: 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-2021-37172 published?: CVE-2021-37172 was published on 2021-08-10 and last updated on 2026-06-17.

References

https://cert-portal.siemens.com/productcert/pdf/ssa-830194.pdf

Affected products (2)

cpe:2.3:o:siemens:simatic_s7-1200_cpu_firmware:4.5.0:*:*:*:*:*:*:*
cpe:2.3:a:siemens:simatic_step_7_\(tia_portal\):*:*:*:*:*:*:*:*

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