CVE-2026-76466: Use of Hard-coded Credentials in Cisco Cisco TelePresence Video Communication Server (VCS) Expressway
Description
CVE-2026-76466 is a critical vulnerability in Cisco TelePresence Video Communication Server (VCS) Expressway devices. It involves the use of persistent cookies and insufficient validation of client certificates when TLS Verify Mode is enabled for clustering. An unauthenticated remote attacker with network access could exploit this flaw to execute arbitrary operating system commands as root on the affected device.
CVSS v3.1
Score 9.8critical
Affected software
Cisco
Cisco TelePresence Video Communication Server (VCS) Expressway
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability affects the database service feature of Cisco Expressway Series devices (Expressway-C and Expressway-E). The root cause includes the use of persistent cookies and lack of proper client certificate validation under certain TLS configurations. An attacker possessing these cookies can connect to the database service and invoke specific RPC commands, resulting in arbitrary command execution with root privileges on the underlying OS. The CVSS v3.1 base score is 9.8, indicating a critical severity level.
Potential Impact
Successful exploitation allows an unauthenticated remote attacker to execute arbitrary commands as root on the affected Cisco Expressway device. This compromises confidentiality, integrity, and availability of the system, potentially leading to full system takeover.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict network access to the Cisco Expressway devices and disable clustering TLS Verify Mode if possible to reduce exposure.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- cisco
- Date Reserved
- 2026-08-19T12:02:03.638Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ad8e8d44d27ba8daac3b6c1
Added to database: 10/21/2026, 16:31:16 UTC
Last enriched: 10/21/2026, 16:46:50 UTC
Last updated: 10/21/2026, 16:55:28 UTC
Views: 3
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
External Links
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.