How severe is CVE-2021-31894?

CVE-2021-31894 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-31894 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-31894?

CVE-2021-31894 primarily affects Siemens Simatic Pcs 7 Firmware. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-31894?

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-2021-31894 published?

CVE-2021-31894 was published on 2021-07-13 and last updated on 2026-06-17.

CVE-2021-31894

CVE-2021-31894 is a high-severity vulnerability in Siemens Simatic Pcs 7 Firmware with a CVSS 3.x base score of 8.8. 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-732.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 7.2
EPSS exploit prediction: 0% (13th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-732
Affected product: Siemens Simatic Pcs 7 Firmware
Published: 2021-07-13
Last modified: 2026-06-17

Description

A vulnerability has been identified in SIMATIC PCS 7 V8.2 and earlier (All versions), SIMATIC PCS 7 V9.X (All versions < V9.1 SP2), SIMATIC PDM (All versions < V9.2 SP2), SIMATIC STEP 7 V5.X (All versions < V5.7), SINAMICS STARTER (containing STEP 7 OEM version) (All versions < V5.4 SP2 HF1). A directory containing metafiles relevant to devices' configurations has write permissions. An attacker could leverage this vulnerability by changing the content of certain metafiles and subsequently manipulate parameters or behavior of devices that would be later configured by the affected software.

Frequently asked questions

What is CVE-2021-31894?: A vulnerability has been identified in SIMATIC PCS 7 V8.2 and earlier (All versions), SIMATIC PCS 7 V9.X (All versions < V9.1 SP2), SIMATIC PDM (All versions < V9.2 SP2), SIMATIC STEP 7 V5.X (All versions < V5.7), SINAMICS STARTER (containing STEP 7 OEM version) (All versions < V5.4 SP2 HF1). A directory containing metafiles relevant to devices' configurations has write permissions. An attacker could leverage this vulnerability by changing the content of certain metafiles and subsequently manipulate parameters or behavior of devices that would be later configured by the affected software.
How severe is CVE-2021-31894?: CVE-2021-31894 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-31894 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-31894?: CVE-2021-31894 primarily affects Siemens Simatic Pcs 7 Firmware. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-31894?: 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-2021-31894 published?: CVE-2021-31894 was published on 2021-07-13 and last updated on 2026-06-17.

References

https://cert-portal.siemens.com/productcert/pdf/ssa-661034.pdf

Affected products (11)

cpe:2.3:o:siemens:simatic_pcs_7_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_pcs_7_firmware:9.0:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_pdm_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_step_7_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:sinamics_starter_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:sinamics_starter_firmware:5.4:-:*:*:*:*:*:*
cpe:2.3:o:siemens:sinamics_starter_firmware:5.4:hf1:*:*:*:*:*:*
cpe:2.3:o:siemens:sinamics_starter_firmware:5.4:hf2:*:*:*:*:*:*
cpe:2.3:o:siemens:sinamics_starter_firmware:5.4:sp1:*:*:*:*:*:*
cpe:2.3:o:siemens:sinamics_starter_firmware:5.4:sp1_hf1:*:*:*:*:*:*
cpe:2.3:o:siemens:sinamics_starter_firmware:5.4:sp2:*:*:*:*:*:*

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