As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Expressway Series software engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening release that addresses multiple internally discovered vulnerabilities. These vulnerabilities were found during internal testing and are not known to be actively exploited. To assist customers in patching and streamline the disclosure process, Cisco has grouped these issues by their underlying vulnerability class - Common Weakness Enumeration (CWE) - and assigned a single Common Vulnerabilities and Exposures identifier (CVE ID) to each CWE grouping. Cisco Expressway Series refers to Cisco Expressway Core (Expressway-C) devices and Cisco Expressway Edge (Expressway-E) devices. Note: Cisco may publish separate security advisories that provide additional details about individual vulnerabilities that are addressed in this release. Cisco has released a software update that addresses these vulnerabilities. There are no workarounds that address these vulnerabilities. This advisory is part of a group of advisories. For a complete list of the advisories and links to them, see Cisco Advance Notification for Publication of October 21, 2026, Security Advisories ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-notice-QGwHnJ6k"].

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Expressway Series software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.   The vulnerabilities tracked by CVE-2026-76491 are related to issues concerning reachable assertions that are grouped under the Common Weakness Enumeration (CWE) Base CWE-617.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Expressway Series software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.  

The vulnerabilities tracked by CVE-2026-76491 are related to issues concerning reachable assertions that are grouped under the Common Weakness Enumeration (CWE) Base CWE-617.