How severe is CVE-2021-37199?

CVE-2021-37199 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-2021-37199 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-37199?

CVE-2021-37199 primarily affects Siemens Sinumerik 808d 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-2021-37199?

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-2021-37199 published?

CVE-2021-37199 was published on 2021-10-12 and last updated on 2026-06-17.

CVE-2021-37199

CVE-2021-37199 is a high-severity vulnerability in Siemens Sinumerik 808d 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-787.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 7.8
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Siemens Sinumerik 808d Firmware
Published: 2021-10-12
Last modified: 2026-06-17

Description

A vulnerability has been identified in SINUMERIK 808D (All versions), SINUMERIK 828D (All versions < V4.95). Affected devices don't process correctly certain special crafted packets sent to port 102/tcp, which could allow an attacker to cause a denial-of-service in the device.

Frequently asked questions

What is CVE-2021-37199?: A vulnerability has been identified in SINUMERIK 808D (All versions), SINUMERIK 828D (All versions < V4.95). Affected devices don't process correctly certain special crafted packets sent to port 102/tcp, which could allow an attacker to cause a denial-of-service in the device.
How severe is CVE-2021-37199?: CVE-2021-37199 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-2021-37199 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-37199?: CVE-2021-37199 primarily affects Siemens Sinumerik 808d 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-2021-37199?: 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-2021-37199 published?: CVE-2021-37199 was published on 2021-10-12 and last updated on 2026-06-17.

References

https://cert-portal.siemens.com/productcert/pdf/ssa-178380.pdf

Affected products (2)

cpe:2.3:o:siemens:sinumerik_808d_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:sinumerik_828d_firmware:*:*:*:*:*:*:*:*

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