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Vulnerability record · CVE-2021-34566 · published 9 November 2022

CVE-2021-34566: Wago 750-8100 firmware classic buffer overflow vulnerability

Wago · 750 8100 Firmware

In WAGO I/O-Check Service in multiple products an unauthenticated remote attacker can send a specially crafted packet containing OS commands to crash the iocheck process and write memory resulting in loss of integrity and DoS.

9.1 CVSS 3.1 Critical EPSS 1.1% · top 35.6% CWE-120 · Classic buffer overflow
9.1CVSS 3.1 base score
1.1%EPSS exploitation probability, 30 days
NoNot in CISA KEV
49Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

In WAGO I/O-Check Service in multiple products an unauthenticated remote attacker can send a specially crafted packet containing OS commands to crash the iocheck process and write memory resulting in loss of integrity and DoS.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Affected products

49 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://cert.vde.com/en/advisories/VDE-2020-036/ Vendor Advisory
https://cert.vde.com/en/advisories/VDE-2020-036/ Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2021-34569Wago 750-8100 firmware out-of-bounds write vulnerabilityIn WAGO I/O-Check Service in multiple products an attacker can send a specially crafted packet containing OS commands to crash the diagnostic tool an…EPSS 0.86%8.2CVE-2021-34567Wago 750-8100 firmware out-of-bounds read vulnerabilityIn WAGO I/O-Check Service in multiple products an unauthenticated remote attacker can send a specially crafted packet containing OS commands to provo…EPSS 0.82%7.8CVE-2020-12069Pilz pmc vulnerabilityIn CODESYS V3 products in all versions prior V3.5.16.0 containing the CmpUserMgr, the CODESYS Control runtime system stores the online communication …EPSS 0.16%7.5CVE-2021-34568Wago 750-8100 firmware allocation without limits vulnerabilityIn WAGO I/O-Check Service in multiple products an unauthenticated remote attacker can send a specially crafted packet containing OS commands to provo…EPSS 1.1%7.5CVE-2022-3281Wago 750-8100 firmware vulnerabilityWAGO Series PFC100/PFC200, Series Touch Panel 600, Compact Controller CC100 and Edge Controller in multiple versions are prone to a loss of MAC-Addre…EPSS 0.73%5.4CVE-2022-22511Wago 750-8100 firmware cross-site scripting vulnerabilityVarious configuration pages of the device are vulnerable to reflected XSS (Cross-Site Scripting) attacks. An authorized attacker with user privileges…EPSS 0.56%5.5CVE-2025-43520Apple OS kernel memory corruption via malicious appA memory corruption flaw (classic buffer overflow) in Apple's kernel was fixed across iOS, iPadOS, macOS, tvOS, visionOS and watchOS. A malicious app…KEVEPSS 0.43%analysed8.8CVE-2025-31277Apple WebKit memory corruption via malicious web contentApple WebKit fails to handle memory correctly when processing crafted web content, leading to memory corruption across Safari, iOS, iPadOS, macOS, tv…KEVEPSS 1.6%analysed

Source: NIST National Vulnerability Database (record CVE-2021-34566), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.