How severe is CVE-2021-20999?

CVE-2021-20999 has a CVSS 3.x base score of 9.4, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability high.

Is CVE-2021-20999 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (57th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20999?

CVE-2021-20999 primarily affects Weidmueller Uc20-wl2000-ac Firmware. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-20999?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-20999 published?

CVE-2021-20999 was published on 2021-05-13 and last updated on 2026-06-17.

CVE-2021-20999

CVE-2021-20999 is a critical-severity vulnerability in Weidmueller Uc20-wl2000-ac Firmware with a CVSS 3.x base score of 9.4. 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-668.

Key facts

Severity: Critical (CVSS 3.x base score 9.4)
CVSS v2: 7.5
EPSS exploit prediction: 1% (57th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-668
Affected product: Weidmueller Uc20-wl2000-ac Firmware
Published: 2021-05-13
Last modified: 2026-06-17

Description

In Weidmüller u-controls and IoT-Gateways in versions up to 1.12.1 a network port intended only for device-internal usage is accidentally accessible via external network interfaces. By exploiting this vulnerability the device may be manipulated or the operation may be stopped.

Frequently asked questions

What is CVE-2021-20999?: In Weidmüller u-controls and IoT-Gateways in versions up to 1.12.1 a network port intended only for device-internal usage is accidentally accessible via external network interfaces. By exploiting this vulnerability the device may be manipulated or the operation may be stopped.
How severe is CVE-2021-20999?: CVE-2021-20999 has a CVSS 3.x base score of 9.4, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability high.
Is CVE-2021-20999 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (57th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20999?: CVE-2021-20999 primarily affects Weidmueller Uc20-wl2000-ac Firmware. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-20999?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-20999 published?: CVE-2021-20999 was published on 2021-05-13 and last updated on 2026-06-17.

References

https://cert.vde.com/en-us/advisories/vde-2021-016

Affected products (12)

cpe:2.3:o:weidmueller:uc20-wl2000-ac_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:weidmueller:uc20-wl2000-ac_firmware:1.11.0:*:*:*:*:*:*:*
cpe:2.3:o:weidmueller:uc20-wl2000-ac_firmware:1.12.1:*:*:*:*:*:*:*
cpe:2.3:o:weidmueller:uc20-wl2000-iot_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:weidmueller:uc20-wl2000-iot_firmware:1.11.0:*:*:*:*:*:*:*
cpe:2.3:o:weidmueller:uc20-wl2000-iot_firmware:1.12.1:*:*:*:*:*:*:*
cpe:2.3:o:weidmueller:iot-gw30_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:weidmueller:iot-gw30_firmware:1.11.0:*:*:*:*:*:*:*
cpe:2.3:o:weidmueller:iot-gw30_firmware:1.12.1:*:*:*:*:*:*:*
cpe:2.3:o:weidmueller:iot-gw30-4g-eu_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:weidmueller:iot-gw30-4g-eu_firmware:1.11.0:*:*:*:*:*:*:*
cpe:2.3:o:weidmueller:iot-gw30-4g-eu_firmware:1.12.1:*:*:*:*:*:*:*

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