How severe is CVE-2021-42029?

CVE-2021-42029 has a CVSS 3.x base score of 7.8, 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-2021-42029 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-42029?

CVE-2021-42029 primarily affects Siemens Simatic Step 7. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-42029?

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-2021-42029 published?

CVE-2021-42029 was published on 2022-04-12 and last updated on 2026-06-17.

CVE-2021-42029

CVE-2021-42029 is a high-severity vulnerability in Siemens Simatic Step 7 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-284.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 7.2
EPSS exploit prediction: 0% (14th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-284
Affected product: Siemens Simatic Step 7
Published: 2022-04-12
Last modified: 2026-06-17

Description

A vulnerability has been identified in SIMATIC STEP 7 (TIA Portal) V15 (All versions), SIMATIC STEP 7 (TIA Portal) V16 (All versions < V16 Update 5), SIMATIC STEP 7 (TIA Portal) V17 (All versions < V17 Update 2). An attacker could achieve privilege escalation on the web server of certain devices due to improper access control vulnerability in the engineering system software. The attacker needs to have direct access to the impacted web server.

Frequently asked questions

What is CVE-2021-42029?: A vulnerability has been identified in SIMATIC STEP 7 (TIA Portal) V15 (All versions), SIMATIC STEP 7 (TIA Portal) V16 (All versions < V16 Update 5), SIMATIC STEP 7 (TIA Portal) V17 (All versions < V17 Update 2). An attacker could achieve privilege escalation on the web server of certain devices due to improper access control vulnerability in the engineering system software. The attacker needs to have direct access to the impacted web server.
How severe is CVE-2021-42029?: CVE-2021-42029 has a CVSS 3.x base score of 7.8, 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-2021-42029 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-42029?: CVE-2021-42029 primarily affects Siemens Simatic Step 7. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-42029?: 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-2021-42029 published?: CVE-2021-42029 was published on 2022-04-12 and last updated on 2026-06-17.

References

https://cert-portal.siemens.com/productcert/pdf/ssa-350757.pdf

Affected products (8)

cpe:2.3:a:siemens:simatic_step_7:*:*:*:*:*:*:*:*
cpe:2.3:a:siemens:simatic_step_7:16:-:*:*:*:*:*:*
cpe:2.3:a:siemens:simatic_step_7:16:update1:*:*:*:*:*:*
cpe:2.3:a:siemens:simatic_step_7:16:update2:*:*:*:*:*:*
cpe:2.3:a:siemens:simatic_step_7:16:update3:*:*:*:*:*:*
cpe:2.3:a:siemens:simatic_step_7:16:update4:*:*:*:*:*:*
cpe:2.3:a:siemens:simatic_step_7:17:-:*:*:*:*:*:*
cpe:2.3:a:siemens:simatic_step_7:17:update1:*:*:*:*:*:*

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