Cisco Expressway Series Remote Code Execution Vulnerability

Description

A vulnerability in the database service feature of Cisco Expressway Series could allow an unauthenticated, remote attacker with network access to a Cisco Expressway device to execute arbitrary operating system commands as root . This vulnerability is due to the use of persistent cookies. Additionally, there is insufficient validation of client certificates when the TLS Verify Mode is set to Enabled for clustering, which means that client certificates are not validated. An attacker with possession of the cookies could exploit this vulnerability by connecting to the database service and invoking specific remote procedure call (RPC) commands. A successful exploit could allow the attacker to execute arbitrary commands as root on the underlying operating system of an affected device. Note: Cisco Expressway Series refers to Cisco Expressway Core (Expressway-C) devices and Cisco Expressway Edge (Expressway-E) devices. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-vcs-static-cred-hr7EWZ8t 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 . In addition, for further documentation of improvements and fixes in Cisco Expressway Series see Cisco Expressway Series Security Hardening Release: October 2026 . Security Impact Rating: Critical CVE: CVE-2026-76466

What to do

Install the fixed versions listed in the official advisory. If you cannot update right away, apply the workarounds or mitigations it describes and limit access to the affected service.

Details

Vendor

Cisco

Product

Cisco Expressway

CVE

CVE-2026-76466

Affected versions

Cisco TelePresence Video Communication Server (VCS) Expressw 8.11: 5 versions, from X8.11.0 to X8.11.4
Cisco TelePresence Video Communication Server (VCS) Expressw 8.6: X8.6; X8.6.1
Cisco TelePresence Video Communication Server (VCS) Expressw 8.2: X8.2; X8.2.1; X8.2.2
Cisco TelePresence Video Communication Server (VCS) Expressw 8.8: 4 versions, from X8.8 to X8.8.3
Cisco TelePresence Video Communication Server (VCS) Expressw 12.5: 10 versions, from X12.5.0 to X12.5.9
Cisco TelePresence Video Communication Server (VCS) Expressw 8.1: X8.1; X8.1.1; X8.1.2
Cisco TelePresence Video Communication Server (VCS) Expressw 8.9: X8.9; X8.9.1; X8.9.2
Cisco TelePresence Video Communication Server (VCS) Expressw 8.7: 4 versions, from X8.7 to X8.7.3
Cisco TelePresence Video Communication Server (VCS) Expressw 12.6: 5 versions, from X12.6.0 to X12.6.4
Cisco TelePresence Video Communication Server (VCS) Expressw 8.5: 4 versions, from X8.5 to X8.5.3
Cisco TelePresence Video Communication Server (VCS) Expressw 8.10: 5 versions, from X8.10.0 to X8.10.4
Cisco TelePresence Video Communication Server (VCS) Expressw 12.7: X12.7.0; X12.7.1
Cisco TelePresence Video Communication Server (VCS) Expressw 14.0: 12 versions, from X14.0.0 to X14.0.11
Cisco TelePresence Video Communication Server (VCS) Expressw 14.2: 6 versions, from X14.2.0 to X14.2.7
Cisco TelePresence Video Communication Server (VCS) Expressw 14.3: 8 versions, from X14.3.0 to X14.3.7
Cisco TelePresence Video Communication Server (VCS) Expressw 15.0: 4 versions, from X15.0.0 to X15.0.3
Cisco TelePresence Video Communication Server (VCS) Expressw 15.2: 6 versions, from X15.2.0 to X15.2.4
Cisco TelePresence Video Communication Server (VCS) Expressw 15.3: X15.3.0; X15.3.1; X15.3.2
Cisco TelePresence Video Communication Server (VCS) Expressw 15.4: X15.4.0
Cisco TelePresence Video Communication Server (VCS) Expressw 15.5: 4 versions, from X15.5.0 to X15.5.3 (from the advisory and NVD; check the exact builds in the official advisory)

CVSS score

9.8

Actively exploited

Not known at this time

Source

Cisco PSIRT – original advisory

Published

October 21, 2026

The description and the recommended action are quoted from the public advisory (the action is our generic advice); severity, exploitation status and affected versions are compiled automatically from public sources and may contain errors. The vendor's original advisory prevails: check it before taking action. This information is provided without warranty and does not replace a professional assessment.