Is CVE-2026-76466 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-76466 being exploited in the wild.

How severe is CVE-2026-76466?

Critical severity, with a CVSS score of 9.8, published 21 October 2026.

Which products and versions are affected?

Cisco Expressway-C X14 and earlier, X15.5.3 and earlier; Cisco Expressway-E X14 and earlier, X15.5.3 and earlier.

Is there a fix for CVE-2026-76466?

Yes: fixed in Expressway-C and Expressway-E: X15.5.20 and later (X14 users must migrate to a fixed release). Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-76466 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-76466?

Check whether you run Cisco Expressway-C or Cisco Expressway-E at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-76466: Cisco Expressway Series remote code execution in database service

CVE-2026-76466 · Severity: critical · CVSS 9.8 · Published 2026-10-21

Cisco Expressway is a video communication system that connects internal networks to external endpoints. An unauthenticated attacker on the network can execute arbitrary commands as root on Expressway devices configured in a cluster, due to insecure persistent cookies and insufficient certificate validation. A successful attack grants complete control over the affected device, enabling data theft, service disruption, or lateral movement into the network.

Technologies: Cisco Expressway-C, Cisco Expressway-E. Vendors: Cisco.

Quick answers

Is CVE-2026-76466 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-76466 being exploited in the wild.
How severe is CVE-2026-76466?: Critical severity, with a CVSS score of 9.8, published 21 October 2026.
Which products and versions are affected?: Cisco Expressway-C X14 and earlier, X15.5.3 and earlier; Cisco Expressway-E X14 and earlier, X15.5.3 and earlier.
Is there a fix for CVE-2026-76466?: Yes: fixed in Expressway-C and Expressway-E: X15.5.20 and later (X14 users must migrate to a fixed release). Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-76466 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-76466?: Check whether you run Cisco Expressway-C or Cisco Expressway-E at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: Expressway-C and Expressway-E: X15.5.20 and later (X14 users must migrate to a fixed release)

Technical details

The vulnerability stems from the use of persistent cookies in the database service feature without proper authentication checks, combined with insufficient validation of client certificates when TLS Verify Mode is enabled for clustering. An attacker with network access can connect to the database service and invoke remote procedure call (RPC) commands to execute arbitrary operating system commands as root. The attack requires the affected device to be configured in a cluster but does not require authentication or user interaction.

Affected products

Cisco Expressway-C X14 and earlier, X15.5.3 and earlier
Cisco Expressway-E X14 and earlier, X15.5.3 and earlier

Timeline

2026-10-21: disclosed

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-vcs-static-cred-hr7EWZ8t

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