CVE-2026-20242

Name of the Vulnerable Software and Affected Versions Cisco Secure Firewall Management Center (FMC) Software (affected versions not specified)

Description A flaw in the External Database Access feature allows an unauthenticated remote attacker to execute arbitrary commands with root privileges. The issue stems from insecure deserialization of a user-supplied Java byte stream—a process where data is converted back into an object—originating from a host configured in the external database access list. An attacker with control over such a host can send a crafted serialized Java byte stream to a specific TCP port to gain root access. The attack surface is reduced if the management interface lacks public internet access.

Recommendations Update the software to the fixed release provided by Cisco. Restrict access to the External Database Access feature to only trusted hosts to minimize the risk of exploitation.