Executive brief
Cisco IOS XR Software contains multiple internally discovered vulnerabilities related to improper handling of user input and command processing. An attacker with network access could exploit these weaknesses to achieve remote code execution, bypass authentication, or cause denial of service on network devices running IOS XR. Cisco has released patched software versions to address these issues, which affect all IOS XR releases.
Technical details
CVE-2026-20278 is one of seven vulnerabilities grouped under a comprehensive security hardening release for Cisco IOS XR Software. This specific CVE addresses improper neutralization issues (CWE-707), which include improper handling of special elements in commands and inadequate input validation. The vulnerabilities affect all releases of Cisco IOS XR Software, including IOS XR7 (LNT), with no authentication or special configuration required for exploitation. An unauthenticated remote attacker can exploit these network-accessible vulnerabilities to achieve high-impact outcomes including remote code execution, information disclosure, or system compromise. Cisco has released fixed software versions and approximately 16 Standalone Maintenance Updates (SMUs) per release to remediate these issues; no workarounds are available.
Affected products
- Cisco IOS XR all releases
Timeline
- 2026-09-02: disclosed: Advisory published