Cisco FMC flaw was exploited by Interlock weeks before patch (CVE-2026-20131)

CVE-2025-20393 is an improper input validation flaw (CWE-20) in Cisco Secure Email Gateway, Secure Email, AsyncOS software, and Web Manager appliances that lets attackers execute arbitrary commands with root privileges on the underlying operating system. The flaw is triggered when an affected appliance processes improperly validated input, though the CISA record does not specify the access vector or whether authentication is required. Successful exploitation yields full compromise of the appliance at the highest OS privilege level, which is significant because these devices sit in the email- and web-security path of enterprise networks. Organizations running these Cisco appliances are affected; CVSS has not yet been published and no public proof-of-concept is known. Exploitation is confirmed in the wild: CISA added the vulnerability to the KEV catalog on 2025-12-17, EPSS estimates a 29.9% chance of exploitation within 30 days (98th percentile), and ransomware use remains undetermined.

Do: Apply the mitigations or updates Cisco specifies in its advisory for CVE-2025-20393 without waiting for a CVSS score; the CISA KEV entry directs users to vendor mitigations, applicable BOD 22-01 cloud-service guidance, or discontinuing use if mitigations are unavailable. Because this record contains no fixed-release details, check the Cisco PSIRT advisory for the exact patched AsyncOS and Web Manager versions before planning the upgrade. In the meantime, review appliance logs and configurations for signs of unexpected command execution or changes, since active exploitation is confirmed and ransomware use is still unknown.

CVE-2026-20045 is an unauthenticated, remote command-execution flaw in Cisco Unified Communications Manager (including Session Management Edition), Unified CM IM & Presence Service, Unity Connection, and Webex Calling Dedicated Instance. It is caused by improper validation of user-supplied input in HTTP requests, and is triggered by sending a sequence of crafted HTTP requests to the web-based management interface of an affected device. A successful exploit gives the attacker user-level access to the underlying operating system, which can then be elevated to root — the reason Cisco assigned a Critical Security Impact Rating on top of the 9.8 CVSS score. The affected products are core enterprise call-control and voicemail platforms used by large organizations, plus Cisco-hosted Webex Calling Dedicated Instances. The flaw is being exploited in the wild: CISA added it to the Known Exploited Vulnerabilities catalog on 2026-01-21 and news reports describe active probing, though no public proof-of-concept code is known and ransomware use is listed as unknown.

Do: Upgrade all five affected products (Unified CM, Unified CM SME, Unified CM IM&P, Unity Connection, and Webex Calling Dedicated Instance) to the fixed releases listed in Cisco's advisory, as this data does not specify version numbers. Until patched, restrict access to the web-based management interface to trusted management networks and monitor affected servers for suspicious HTTP request sequences and webshells. Federal agencies must apply vendor mitigations per CISA BOD 22-01 guidance or discontinue use, following the KEV listing of 2026-01-21.

A flaw in the peering authentication mechanism of Cisco Catalyst SD-WAN Controller (formerly vSmart), Manager (formerly vManage), and Validator (formerly vBond) allows an unauthenticated, remote attacker to bypass authentication by sending crafted requests to an affected system. A successful exploit grants the attacker access as an internal, high-privileged, non-root user on the SD-WAN Controller, from which they can reach NETCONF and manipulate the network configuration of the entire SD-WAN fabric. Any organization operating these Cisco SD-WAN control-plane components is affected, and the critical CVSS 10.0 score reflects full network scope with no privileges or user interaction required. The flaw is confirmed exploited in the wild: CISA added it to the KEV on 2026-02-25, Cisco has confirmed active exploitation (including a compromise of a communications service provider), and Five Eyes allies have issued an active-exploitation warning, with EPSS at 88.2% (100th percentile).

Do: Upgrade affected Catalyst SD-WAN Controller, Manager, and Validator components per Cisco's PSIRT advisory (fixed versions are not specified in this data), and prioritize patching given confirmed in-the-wild exploitation. Follow CISA Emergency Directive 26-03 and the CISA Hunt & Hardening Guidance for Cisco SD-WAN Devices: hunt for compromise indicators such as unexpected high-privileged non-root logins and unauthorized NETCONF configuration changes, and restrict internet exposure of SD-WAN management interfaces. Where mitigations are unavailable, adhere to applicable BOD 22-01 cloud guidance or discontinue use of the product.

CVE-2026-20131 is a deserialization of untrusted data flaw (CWE-502) in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management. An unauthenticated, remote attacker can trigger it by sending crafted serialized data to the exposed management interface. Successful exploitation allows the attacker to execute arbitrary Java code as root on the affected device, giving full control of the central platform that manages Cisco firewall policy. Any organization running FMC or managing firewalls through SCC is potentially affected; specific version ranges have not yet been published in the available data. The flaw was added to CISA KEV on 2026-03-19 with known ransomware use, and EPSS assigns a ~31% probability of exploitation within 30 days (98th percentile), though no public proof-of-concept is known.

Do: Check Cisco's advisory for fixed releases and upgrade all FMC and SCC-managed deployments as soon as patched versions are identified, since version ranges are not yet in this data; until patched, restrict the FMC/SCC web-based management interface to trusted management networks or VPN access. Given the CISA KEV listing (added 2026-03-19) with known ransomware use, treat this as a high-priority patch and confirm whether BOD 22-01 remediation deadlines apply to your organization.