How severe is CVE-2020-27632?

CVE-2020-27632 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-2020-27632 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-27632?

CVE-2020-27632 primarily affects Siemens Simatic Mv420 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-2020-27632?

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-2020-27632 published?

CVE-2020-27632 was published on 2021-03-10 and last updated on 2026-06-17.

CVE-2020-27632

CVE-2020-27632 is a high-severity vulnerability in Siemens Simatic Mv420 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.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (65th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Siemens Simatic Mv420 Firmware
Published: 2021-03-10
Last modified: 2026-06-17

Description

In SIMATIC MV400 family versions prior to v7.0.6, the ISN generator is initialized with a constant value and has constant increments. An attacker could predict and hijack TCP sessions.

Frequently asked questions

What is CVE-2020-27632?: In SIMATIC MV400 family versions prior to v7.0.6, the ISN generator is initialized with a constant value and has constant increments. An attacker could predict and hijack TCP sessions.
How severe is CVE-2020-27632?: CVE-2020-27632 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-2020-27632 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-27632?: CVE-2020-27632 primarily affects Siemens Simatic Mv420 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-2020-27632?: 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-2020-27632 published?: CVE-2020-27632 was published on 2021-03-10 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:o:siemens:simatic_mv420_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_mv440_firmware:*:*:*:*:*:*:*:*

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