CVE-2021-21000: WAGO: PFC200 Denial of Service due to the number of connections to the runtime

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-05-24 · updated 2026-06-17
Weakness: CWE-770

Description

On WAGO PFC200 devices in different firmware versions with special crafted packets an attacker with network access to the device could cause a denial of service for the login service of the runtime.

Affected products

WAGO 750-8202 Firmware: before 03.06.19_\(18\) — fixed in 03.06.19_\(18\)
WAGO 750-8203 Firmware: before 03.06.19_\(18\) — fixed in 03.06.19_\(18\)
WAGO 750-8204 Firmware: before 03.06.19_\(18\) — fixed in 03.06.19_\(18\)
WAGO 750-8206 Firmware: before 03.06.19_\(18\) — fixed in 03.06.19_\(18\)
WAGO 750-8207 Firmware: before 03.06.19_\(18\) — fixed in 03.06.19_\(18\)
WAGO 750-8208 Firmware: before 03.06.19_\(18\) — fixed in 03.06.19_\(18\)
WAGO 750-8210 Firmware: before 03.06.19_\(18\) — fixed in 03.06.19_\(18\)
WAGO 750-8211 Firmware: before 03.06.19_\(18\) — fixed in 03.06.19_\(18\)
WAGO 750-8212 Firmware: before 03.06.19_\(18\) — fixed in 03.06.19_\(18\)
WAGO 750-8213 Firmware: before 03.06.19_\(18\) — fixed in 03.06.19_\(18\)
WAGO 750-8214 Firmware: before 03.06.19_\(18\) — fixed in 03.06.19_\(18\)
WAGO 750-8216 Firmware: before 03.06.19_\(18\) — fixed in 03.06.19_\(18\)
WAGO 750-8217 Firmware: before 03.06.19_\(18\) — fixed in 03.06.19_\(18\)
WAGO 750-823 Firmware: before fw08 — fixed in fw08
WAGO 750-829 Firmware: before fw15 — fixed in fw15
WAGO 750-831 Firmware: before fw15 — fixed in fw15
WAGO 750-832 Firmware: before fw08 — fixed in fw08
WAGO 750-852 Firmware: before fw15 — fixed in fw15
WAGO 750-862 Firmware: before fw08 — fixed in fw08
WAGO 750-880 Firmware: before fw16 — fixed in fw16
WAGO 750-881 Firmware: before fw15 — fixed in fw15
WAGO 750-882 Firmware: before fw15 — fixed in fw15
WAGO 750-885 Firmware: before fw15 — fixed in fw15
WAGO 750-889 Firmware: before fw15 — fixed in fw15
WAGO 750-890 Firmware: before fw08 — fixed in fw08
WAGO 750-891 Firmware: before fw08 — fixed in fw08
WAGO 750-893 Firmware: before fw08 — fixed in fw08

How to fix

Upgrade to a fixed version: WAGO 750-8202 Firmware 03.06.19_\(18\); WAGO 750-8203 Firmware 03.06.19_\(18\); WAGO 750-8204 Firmware 03.06.19_\(18\); WAGO 750-8206 Firmware 03.06.19_\(18\); WAGO 750-8207 Firmware 03.06.19_\(18\); WAGO 750-8208 Firmware 03.06.19_\(18\); WAGO 750-8210 Firmware 03.06.19_\(18\); WAGO 750-8211 Firmware 03.06.19_\(18\); WAGO 750-8212 Firmware 03.06.19_\(18\); WAGO 750-8213 Firmware 03.06.19_\(18\); WAGO 750-8214 Firmware 03.06.19_\(18\); WAGO 750-8216 Firmware 03.06.19_\(18\). Check the vendor advisory for mitigations.

References

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