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CVE-2021-31886 is a stack-based buffer overflow in the Nucleus FTP server used by Siemens APOGEE, Desigo, TALON, Nucleus, and affected WAGO PLC products. The FTP service fails to validate the length of an attacker-supplied username in the pre-authentication USER command. An oversized value can overwrite stack memory and alter control flow, resulting in denial of service or arbitrary code execution. The condition has been demonstrated on an affected WAGO PLC with attacker-supplied ARM shellcode executing in an Ethernet receive callback context.
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No public exploit code observed for this vulnerability.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
12 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A pre-authentication, stack-based buffer-overflow vulnerability in the Nucleus FTP server USER-command handler that enables remote code execution on affected Nucleus V1-based WAGO PLCs. It was demonstrated as a working RCE exploit capable of executing supplied ARM shellcode and sending attacker-controlled network packets.
A pre-authentication buffer-overflow vulnerability in the Nucleus FTP server deployed on affected WAGO PLCs. It permits an unauthenticated remote attacker to execute arbitrary ARM shellcode; the article describes a working exploit being ported between WAGO 750-852 and 750-831 models.
A pre-authentication buffer overflow in the Nucleus FTP server's handling of the FTP USER command. It enables remote arbitrary code execution on affected devices incorporating the vulnerable Nucleus TCP/IP stack, including specified WAGO PLCs.
A pre-authentication buffer-overflow vulnerability in the Nucleus FTP server that permits remote code execution of arbitrary ARM shellcode on affected PLCs without credentials. Forescout researchers used AI assistance to port and develop a working exploit across two WAGO PLC models.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.