A critical command injection vulnerability has been identified in Rancher, an open-source multi-cluster management platform [S2]. The vulnerability, tracked as CVE-2026-44939, allows an attacker to execute arbitrary commands by providing a specially crafted YAML parameter that is not properly sanitized before being processed by the system [S1][S3].
Impact
Successful exploitation of this vulnerability can lead to full system compromise [S2]. Since Rancher often runs with high privileges to manage Kubernetes clusters, an attacker could gain unauthorized access to sensitive cluster data, modify configurations, or disrupt managed services [S2]. The vulnerability has been assigned a CVSS score of 9.6, reflecting its critical nature [S3].
Root Cause
The root cause is a failure to sanitize user-supplied input within YAML configurations [S2]. Specifically, certain parameters within the YAML structure are passed to underlying system shells or execution environments without adequate validation or escaping, leading to CWE-95 (Improper Neutralization of Directives in Dynamically Evaluated Code) [S1].
Affected Versions
- Rancher versions >= 2.14.0 and < 2.14.2 [S3].
Fixes and Mitigations
Users should upgrade to Rancher version 2.14.2 or later to resolve this issue [S3]. If an immediate upgrade is not possible, ensure that access to the Rancher API and UI is restricted to trusted users and that any YAML-based configurations are strictly audited before application [S2].
How FixVibe could detect it
FixVibe could detect this vulnerability through its repository scanning capabilities [S3]. By analyzing Go-based Rancher deployments and checking the go.mod or version manifests for affected versions (2.14.0 - 2.14.1), FixVibe can alert users to the presence of the vulnerable software [S3].