How severe is CVE-2021-20994?

CVE-2021-20994 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-20994 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20994?

CVE-2021-20994 primarily affects Wago 0852-0303 Firmware. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-20994?

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-2021-20994 published?

CVE-2021-20994 was published on 2021-05-13 and last updated on 2026-06-17.

CVE-2021-20994

CVE-2021-20994 is a high-severity vulnerability in Wago 0852-0303 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-79.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 4.3
EPSS exploit prediction: 1% (46th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Wago 0852-0303 Firmware
Published: 2021-05-13
Last modified: 2026-06-17

Description

In multiple managed switches by WAGO in different versions an attacker may trick a legitimate user to click a link to inject possible malicious code into the Web-Based Management.

Frequently asked questions

What is CVE-2021-20994?: In multiple managed switches by WAGO in different versions an attacker may trick a legitimate user to click a link to inject possible malicious code into the Web-Based Management.
How severe is CVE-2021-20994?: CVE-2021-20994 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-20994 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20994?: CVE-2021-20994 primarily affects Wago 0852-0303 Firmware. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-20994?: 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-2021-20994 published?: CVE-2021-20994 was published on 2021-05-13 and last updated on 2026-06-17.

References

https://cert.vde.com/en-us/advisories/vde-2021-013

Affected products (5)

cpe:2.3:o:wago:0852-0303_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:wago:0852-1305_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:wago:0852-1505_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:wago:0852-1305\/000-001_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:wago:0852-1505\/000-001_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Wago 0852-0303 Firmware

CVE-2021-20998 — Critical (CVSS 10.0): In multiple managed switches by WAGO in different versions without authorization and with specially crafted packets it…
CVE-2021-20997 — High (CVSS 7.5): In multiple managed switches by WAGO in different versions it is possible to read out the password hashes of all…
CVE-2021-20996 — Medium (CVSS 5.3): In multiple managed switches by WAGO in different versions special crafted requests can lead to cookies being…
CVE-2021-20995 — Medium (CVSS 5.3): In multiple managed switches by WAGO in different versions the webserver cookies of the web based UI contain user…
CVE-2021-20993 — Medium (CVSS 5.3): In multiple managed switches by WAGO in different versions the activated directory listing provides an attacker with…

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