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Cisco Security Updates for Expressway, Unified Communications, and Snort 3

Cisco has patched 34 vulnerabilities, including critical-severity remote code execution and authentication bypass flaws, affecting Expressway Series, Unified Communications products, and Snort 3.

CVE search metadata

CVE search record: CVE-2026-76462. Severity: medium. CVSS: 5.5. KEV: no. Product: Expressway Series (< X15.5.20), Unified Communications Manager, Unified Communications Manager IM & Presence Service, Unified Communications Manager Session Management Edition, Unity Connection, Emergency Responder, Prime Collaboration Deployment, Snort 3 (< 3.12.4.0), Cyber Vision (< 3.12.4.0), CDFW (< 3.12.4.0), Meraki MX (< 3.12.4.0), CSA, Secure Firewall ASA (< 3.12.4.0), Secure FMC (< 3.12.4.0), Secure FTD, UTD for IOS XE, IOS XR, Secure Client. Brief: Cisco Security Updates for Expressway, Unified Communications, and Snort 3. Brief link: https://feed.craftedsignal.io/briefs/2026-10-cisco-security-patches/

CVE search record: CVE-2026-76466. Severity: critical. CVSS: 9.8. KEV: no. Product: Expressway Series (< X15.5.20), Unified Communications Manager, Unified Communications Manager IM & Presence Service, Unified Communications Manager Session Management Edition, Unity Connection, Emergency Responder, Prime Collaboration Deployment, Snort 3 (< 3.12.4.0), Cyber Vision (< 3.12.4.0), CDFW (< 3.12.4.0), Meraki MX (< 3.12.4.0), CSA, Secure Firewall ASA (< 3.12.4.0), Secure FMC (< 3.12.4.0), Secure FTD, UTD for IOS XE, IOS XR, Secure Client. Brief: Cisco Security Updates for Expressway, Unified Communications, and Snort 3. Brief link: https://feed.craftedsignal.io/briefs/2026-10-cisco-security-patches/

Triage facts

Revision 1
Applicability
Expressway Series (< X15.5.20), Unified Communications Manager +16
Evidence
Unknown
Severity
High
Action
Elevated
Sources
1 public source
Freshness
Revision 1Oct 22, 10:47 UTC
Vulnerabilities
2 CVEs
Source quality
A1Likely

Cisco released security updates addressing 34 vulnerabilities across multiple product lines, including Expressway Series, Unified Communications products, Snort 3, IOS XR, and Secure Client. The vulnerabilities include critical-severity flaws capable of remote code execution (RCE), authentication bypass, and denial-of-service (DoS). Cisco reports no evidence of active exploitation in the wild as of the release date.

Impact

Successful exploitation of critical vulnerabilities, such as CVE-2026-76466 in the Expressway Series, could allow an unauthenticated attacker to execute arbitrary commands with root privileges on the underlying operating system. Other vulnerabilities in Unified Communications and Snort 3 permit unauthorized resource access, authentication bypass, or arbitrary command execution.

Recommendation

  • Inventory systems running Cisco Expressway Series, Unified Communications Manager (and related products), and Snort 3 deployments.
  • Upgrade Cisco Expressway Series to version X15.5.20 or later.
  • Upgrade Snort 3 to version 3.12.4.0 or later.
  • Apply the corresponding security updates for peripheral products including Cyber Vision, CDFW, Meraki MX, Secure Firewall ASA, Secure FMC, Secure FTD, and UTD for IOS XE.
  • Monitor Cisco’s official security advisories page for specific upgrade paths for impacted Unified Communications products.

Immediate actions

Patch affected Cisco infrastructure to the versions specified in the advisory.

IT Operations 72h

Mitigations

Upgrade Expressway Series to X15.5.20 and Snort 3 to 3.12.4.0.

immediate IT Operations

CVE-2026-76466 and general Snort 3 vulnerabilities.