CVE-2026-54680 in logging-operator
Summary
by MITRE • 07/29/2026
Logging operator automates the deployment and configuration of Kubernetes logging pipelines. Prior to 6.6.0, the Fluentd configuration renderer FluentRender in pkg/sdk/logging/model/render/fluent.go writes CRD strings such as Flow record_transformer.records values directly into fluent.conf without escaping, allowing a user who can create Flow resources to inject a Fluentd <match **> block using @type exec and execute arbitrary commands inside the Fluentd aggregator. This issue is fixed in version 6.6.0.
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Analysis
by VulDB Data Team • 07/29/2026
The vulnerability resides within the logging operator's handling of Kubernetes Custom Resource Definitions, specifically affecting versions prior to 6.6.0 where the Fluentd configuration renderer FluentRender processes Flow record_transformer.records values without proper input sanitization. This flaw represents a critical security weakness that enables privilege escalation through improper data handling in the logging infrastructure component. The vulnerability stems from insufficient output escaping mechanisms during configuration file generation, allowing maliciously crafted CRD strings to be directly embedded into the fluent.conf file without proper sanitization.
The technical implementation of this vulnerability occurs in the pkg/sdk/logging/model/render/fluent.go file where the FluentRender function processes user-supplied Flow resources without adequate validation or escaping procedures. When a malicious actor creates a Flow resource with specially crafted record_transformer.records values, these inputs are directly written into the fluent.conf configuration file without proper sanitization, creating an environment where arbitrary Fluentd directives can be injected. The specific injection point allows for the insertion of <match **> blocks containing @type exec directives, which execute arbitrary commands within the context of the Fluentd aggregator process.
This vulnerability has significant operational impact as it enables attackers with minimal privileges to escalate their access within the Kubernetes cluster through the logging infrastructure. The ability to inject arbitrary command execution via the Fluentd aggregator creates a persistent backdoor mechanism that can be used for data exfiltration, lateral movement, or complete system compromise. The attack vector specifically targets the logging pipeline's configuration management system, which typically runs with elevated privileges necessary for log collection and processing. This issue directly maps to CWE-74 and CWE-94, representing code injection and improper input validation vulnerabilities respectively.
The exploitation of this vulnerability follows a well-defined attack pattern that aligns with ATT&CK technique T1059.007 for command and script execution through fluentd components. An attacker who can create Flow resources within the cluster can leverage this flaw to execute arbitrary commands on the logging aggregator node, potentially gaining access to sensitive log data or using the compromised system as a pivot point for further attacks. The vulnerability exists in the configuration rendering phase, making it particularly dangerous since it affects all legitimate users of the logging operator who have permission to create Flow resources.
The fix implemented in version 6.6.0 addresses this issue by introducing proper input sanitization and escaping mechanisms within the FluentRender function. This mitigation ensures that user-supplied CRD strings are properly validated and escaped before being written into the fluent.conf configuration file, preventing injection of malicious Fluentd directives. The solution follows security best practices for configuration management and input validation, aligning with industry standards for preventing code injection attacks in infrastructure-as-code scenarios. Organizations should immediately upgrade to version 6.6.0 or later to remediate this vulnerability and prevent potential exploitation through the logging pipeline's configuration system.
The broader implications of this vulnerability extend beyond immediate command execution capabilities, as it demonstrates a critical weakness in Kubernetes logging operator security design. The flaw highlights the importance of input validation in configuration management systems and underscores the need for proper privilege separation between different components of the logging infrastructure. This vulnerability serves as a reminder that even seemingly benign configuration management tools can become attack vectors when proper sanitization practices are not implemented, particularly in multi-tenant environments where different users may have varying levels of access to logging resources.