CVE-2026-20276: Cisco IOS XR

High severity, CVSS 8.6. EPSS: 0.3% chance of exploitation in the next 30 days.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XR Software engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20276 are related to insufficient control flow management issues that are grouped under the Common Weakness Enumeration (CWE) CWE-691.

Affected products

• Cisco IOS XR: version 6.5.25 only; version 6.5.26 only; version 6.5.28 only; version 6.5.29 only; version 6.5.31 only; version 6.5.32 only; …

Published 2026-09-02. Last modified 2026-09-18.