Unauthenticated attacker can write files via relative path traversal

Cisco · Secure Email Gateway

Updated October 17, 2026

SeverityCritical

IT Intelligence Analysis

Cisco Secure Email Gateway contains a relative path‑traversal bug that lets an unauthenticated remote actor write arbitrary files to the underlying OS. This enables persistent footholds and potential ransomware payload deployment on the email gateway.

Impact if Unpatched

Attackers could plant malicious scripts or replace email‑gateway binaries, compromising inbound/outbound mail flow and harvesting credentials or encrypted communications.

Remediation Steps

Upgrade to the patched version; isolate the appliance on a dedicated VLAN, enforce strict inbound ACLs, and scan for unexpected files after remediation.

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