CVE-2026-76466

Critical

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.

SeverityCritical
CVSS9.8
Exploit probability—
ProductCisco TelePresence Video Communication Server (VCS) Expressway
PublishedOct 21, 2026
First seenOct 21, 2026

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

ProductAffected versionsFixed in
Cisco Cisco TelePresence Video Communication Server (VCS) ExpresswayX8.11.2, X8.6, X8.11.3, X8.2.2, X8.8.3, X8.11.0, X12.5.2, X8.1.1, X8.9, X12.5.1, X12.5.6, X8.7.3, X12.6.0, X8.11.1, X8.5, X8.9.1, X8.10.2, X8.8.2, X8.5.3, X8.1, X8.9.2, X8.11.4, X12.5.4, X8.8.1, X8.2.1, X8.5.1, X8.6.1, X8.1.2, X8.8, X8.10.0, X12.5.3, X8.10.1, X12.5.7, X8.10.3, X8.7.1, X8.2, X12.5.8, X8.7, X8.5.2, X12.5.9, X12.5.0, X8.10.4, X8.7.2, X12.5.5, X12.6.1, X12.6.2, X12.6.3, X12.6.4, X12.7.0, X12.7.1, X14.0.0, X14.0.1, X14.0.2, X14.0.3, X14.0.4, X14.0.5, X14.0.6, X14.0.7, X14.0.8, X14.2.0, X14.0.9, X14.2.1, X14.2.2, X14.0.11, X14.2.5, X14.0.10, X14.2.6, X14.2.7, X14.3.0, X14.3.1, X14.3.2, X14.3.3, X15.0.0, X14.3.4, X14.3.5, X15.0.1, X15.0.2, X15.0.3, X14.3.6, X15.2.0, X15.2.1, X15.2.2, X15.2.3, X14.3.7, X15.2.4., X15.2.4, X15.3.0, X15.3.1, X15.3.2, X15.4.0, X15.5.0, X15.5.1, X15.5.2, X15.5.3—

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