CVE-2026-93537 in Rancher
Summary
by MITRE • 09/28/2026
A user who can supply bundle content to a repository referenced by a GitRepo resource, for example through Git push access, or through permission to create or modify a GitRepo, can cause SUSE Rancher Fleet to read files from the filesystem of the environment that processes the bundle and include their contents in the generated Bundle resource. This can expose configuration or credential material that the user has no Kubernetes RBAC permission to read, including Helm registry credentials made available to the bundle-processing job when per-path Helm credentials are configured. This affects Fleet 0.16 before 0.16.2, 0.15 before 0.15.7, 0.14 before 0.14.11, 0.13 before 0.13.16, 0.12 before 0.12.20 and potentially older unsupported versions.
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Analysis
by VulDB Data Team • 09/28/2026
The vulnerability described constitutes a critical path traversal or arbitrary file read flaw within SUSE Rancher Fleet, specifically affecting the bundle processing mechanism used to deploy applications via GitOps workflows. This security issue arises from an insufficient validation of user-supplied content when interacting with Git repositories that are referenced by GitRepo resources in Kubernetes clusters. The core technical flaw lies in how Fleet processes bundles derived from these repositories; it fails to adequately sanitize or restrict file paths, allowing a malicious actor who has write access to the associated Git repository to inject specific bundle configurations. By manipulating the bundle content through standard Git operations such as pushing changes or modifying existing files within the repository, an attacker can instruct the Fleet controller to read arbitrary files from the underlying filesystem of the environment executing the bundle processing job rather than limiting reads strictly to the intended repository contents.
This lack of input validation enables a severe information disclosure attack vector where sensitive configuration data and credential material are exposed beyond their authorized scope. Specifically, when per-path Helm credentials are configured for automated deployments, these secrets are typically made available to the bundle-processing jobs via environment variables or mounted volumes with restricted access controls intended to limit visibility to specific service accounts. However, due to this vulnerability, a user with Git push permissions can cause Fleet to read files from the host filesystem of the processing node and include their contents in the generated Bundle resource. This effectively bypasses Kubernetes Role-Based Access Control (RBAC) restrictions because the exposure occurs at the application logic level during bundle generation rather than through direct API access to secret resources, allowing attackers to harvest sensitive data such as Helm registry credentials that they should not have permission to view.
The operational impact of this vulnerability is significant for organizations relying on Fleet for multi-cluster management and GitOps-based deployments. The exposure of internal infrastructure secrets can lead to further compromise of the Kubernetes cluster or connected cloud environments if those credentials are leveraged by an attacker. For instance, stolen Helm registry credentials could allow unauthorized access to private container images, potentially leading to supply chain attacks or deployment of malicious workloads across managed clusters. This vulnerability affects multiple versions of SUSE Rancher Fleet, including 0.16 prior to 0.16.2, 0.15 prior to 0.15.7, 0.14 prior to 0.14.11, 0.13 prior to 0.13.16, and 0.12 prior to 0.12.20, indicating a systemic issue in the bundle processing logic across several major releases that requires immediate attention for all affected deployments.
From a classification perspective, this vulnerability aligns with CWE-59 Improper Link Resolution Before File Access commonly known as path traversal, and potentially CWE-732 Incorrect Permission Assignment for Critical Resource if considering the broader context of privilege escalation through information leakage. In terms of adversary tactics, it maps to ATT&CK technique T1083 File and Directory Discovery, where an attacker explores the system to locate sensitive files, followed by T1552 Unsecured Credentials as they extract stored authentication mechanisms like Helm registry passwords. Mitigation strategies primarily involve upgrading Fleet to a patched version that resolves this input validation deficiency immediately for all active clusters. Additionally, organizations should enforce strict least-privilege principles regarding Git repository access, ensuring that users with push permissions do not have unnecessary influence over bundle processing logic unless explicitly required and monitored. Implementing robust audit logging for bundle generation events can also aid in detecting potential exploitation attempts while patching efforts are underway.