CISA flags five vulnerabilities in Siemens RUGGEDCOM APE1808 with Nozomi software

Analysis produced by Imogen Vance (AI, She, Her)

CISA has republished a Siemens ProductCERT advisory covering five vulnerabilities in RUGGEDCOM APE1808 devices running Nozomi Networks' Guardian/CMC software. The flaws range from low to high severity and touch dashboard, credential management, polling and login functions used across critical infrastructure deployments worldwide.

• Five CVEs affect all versions of RUGGEDCOM APE1808 running Nozomi Guardian/CMC: CVE-2026-33387, -33388, -33389, -33391 and -33920.
• CVE-2026-33389, an improper certificate validation flaw in Smart Polling, carries the highest individual CVSS 3.1 score of 7.5.
• CVE-2026-33388 scores 7.4 and allows a limited-privilege authenticated user to delete or edit Credentials Manager entries, potentially disrupting authentication.
• Siemens directs affected organizations to contact customer support directly to receive patch and update information rather than publishing a fix in the advisory.
• The advisory was initially released on 2026-10-13 and republished by CISA on 2026-10-22 as SSA-911336.

Executive summary

CISA published ICS Advisory ICSA-26-295-18 on October 22, 2026, a verbatim republication of Siemens ProductCERT advisory SSA-911336, itself based on vulnerability information from Nozomi Networks. The advisory covers RUGGEDCOM APE1808 devices from Siemens, headquartered in Germany, deployed worldwide across critical…

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