How severe is CVE-2021-37204?

CVE-2021-37204 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 none, and availability high.

Is CVE-2021-37204 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-37204?

CVE-2021-37204 primarily affects Siemens Simatic Drive Controller Cpu 1504d Tf Firmware. In total, 49 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-37204?

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-2021-37204 published?

CVE-2021-37204 was published on 2022-02-09 and last updated on 2026-06-17.

CVE-2021-37204

CVE-2021-37204 is a high-severity vulnerability in Siemens Simatic Drive Controller Cpu 1504d Tf 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-672.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 7.1
EPSS exploit prediction: 2% (80th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-672
Affected product: Siemens Simatic Drive Controller Cpu 1504d Tf Firmware
Published: 2022-02-09
Last modified: 2026-06-17

Description

A vulnerability has been identified in SIMATIC Drive Controller family (All versions < V2.9.2), SIMATIC Drive Controller family (All versions >= V2.9.2 < V2.9.4), SIMATIC ET 200SP Open Controller CPU 1515SP PC (incl. SIPLUS variants) (All versions), SIMATIC ET 200SP Open Controller CPU 1515SP PC2 (incl. SIPLUS variants) (All versions < V21.9), SIMATIC ET 200SP Open Controller CPU 1515SP PC2 (incl. SIPLUS variants) (All versions >= V21.9 < V21.9.4), SIMATIC ET 200SP Open Controller CPU 1515SP PC2 Ready4Linux (All versions), SIMATIC S7-1200 CPU family (incl. SIPLUS variants) (All versions < V4.5.0), SIMATIC S7-1200 CPU family (incl. SIPLUS variants) (All versions >= V4.5.0 < V4.5.2), SIMATIC S7-1500 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions < V2.9.2), SIMATIC S7-1500 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions >= V2.9.2 < V2.9.4), SIMATIC S7-1500 Software Controller (All versions < V21.9), SIMATIC S7-1500 Software Controller (All versions >= V21.9 < V21.9.4), SIMATIC S7-PLCSIM Advanced (All versions < V4.0), SIMATIC S7-PLCSIM Advanced (All versions >= V4.0 < V4.0 SP1), SIPLUS TIM 1531 IRC (All versions < V2.3.6), TIM 1531 IRC (All versions < V2.3.6). An unauthenticated attacker could cause a denial-of-service condition in a PLC when sending specially prepared packet over port 102/tcp. A restart of the affected device is needed to restore normal operations.

Frequently asked questions

What is CVE-2021-37204?: A vulnerability has been identified in SIMATIC Drive Controller family (All versions < V2.9.2), SIMATIC Drive Controller family (All versions >= V2.9.2 < V2.9.4), SIMATIC ET 200SP Open Controller CPU 1515SP PC (incl. SIPLUS variants) (All versions), SIMATIC ET 200SP Open Controller CPU 1515SP PC2 (incl. SIPLUS variants) (All versions < V21.9), SIMATIC ET 200SP Open Controller CPU 1515SP PC2 (incl. SIPLUS variants) (All versions >= V21.9 < V21.9.4), SIMATIC ET 200SP Open Controller CPU 1515SP PC2 Ready4Linux (All versions), SIMATIC S7-1200 CPU family (incl. SIPLUS variants) (All versions < V4.5.0), SIMATIC S7-1200 CPU family (incl. SIPLUS variants) (All versions >= V4.5.0 < V4.5.2), SIMATIC S7-1500 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions < V2.9.2), SIMATIC S7-1500 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions >= V2.9.2 < V2.9.4), SIMATIC S7-1500 Software Controller (All versions < V21.9), SIMATIC S7-1500 Software Controller (All versions >= V21.9 < V21.9.4), SIMATIC S7-PLCSIM Advanced (All versions < V4.0), SIMATIC S7-PLCSIM Advanced (All versions >= V4.0 < V4.0 SP1), SIPLUS TIM 1531 IRC (All versions < V2.3.6), TIM 1531 IRC (All versions < V2.3.6). An unauthenticated attacker could cause a denial-of-service condition in a PLC when sending specially prepared packet over port 102/tcp. A restart of the affected device is needed to restore normal operations.
How severe is CVE-2021-37204?: CVE-2021-37204 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 none, and availability high.
Is CVE-2021-37204 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-37204?: CVE-2021-37204 primarily affects Siemens Simatic Drive Controller Cpu 1504d Tf Firmware. In total, 49 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-37204?: 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-2021-37204 published?: CVE-2021-37204 was published on 2022-02-09 and last updated on 2026-06-17.

References

https://cert-portal.siemens.com/productcert/pdf/ssa-838121.pdf

Affected products (49)

cpe:2.3:o:siemens:simatic_drive_controller_cpu_1504d_tf_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_drive_controller_cpu_1507d_tf_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_et_200sp_open_controller_cpu_1515sp_pc2_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-plcsim_advanced_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-plcsim_advanced_firmware:4.0:-:*:*:*:*:*:*
cpe:2.3:o:siemens:tim_1531_irc_firmware:*:*:*:*:*:*:*:*
cpe:2.3:a:siemens:simatic_s7-1500_software_controller:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1200_cpu_1211c_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1200_cpu_1212c_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1200_cpu_1212fc_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1200_cpu_1214fc_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1200_cpu_1214c_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1200_cpu_1215fc_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1200_cpu_1215c_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1200_cpu_1217c_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1510sp-1_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1510sp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1511-1_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1511c-1_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1511f-1_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1511t-1_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1511tf-1_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1512c-1_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1512sp-1_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1512spf-1_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1513-1_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1513f-1_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1513r-1_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_cpu_1513prof-2_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_cpu_1513pro-2_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1515-2_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1515f-2_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1515r-2_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1515t-2_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1515tf-2_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1516pro_f_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1516pro-2_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1516-3_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1516f-3_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1516t-3_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Siemens Simatic Drive Controller Cpu 1504d Tf Firmware

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