CVE-2026-59284 in Spring Cloud Commons
Summary
by MITRE • 08/27/2026
There is no allow list for property keys when Spring Cloud Commons writable /actuator/env is enabled. Spring Cloud Commons 5.0.0 - 5.0.2 Spring Cloud Commons 4.3.0 - 4.3.3 Spring Cloud Commons 4.0.0 - 4.2.6 Spring Cloud Commons 3.1.10 and earlier
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Analysis
by VulDB Data Team • 08/27/2026
The vulnerability identified in the provided context relates to a critical configuration flaw within the Spring Cloud Commons library, specifically affecting versions ranging from early releases up through version 5.0.2. This issue centers on the absence of an allow list for property keys when accessing the writable /actuator/env endpoint. In modern Java-based microservices architectures built with Spring Boot and Spring Cloud, the Actuator module provides a suite of production-ready features to monitor and manage applications. Among these endpoints is the env endpoint, which allows users to view or modify environment properties dynamically at runtime without restarting the application. While this functionality offers significant operational flexibility for DevOps teams managing complex deployments, it introduces substantial security risks if not properly constrained. The core technical flaw lies in the fact that when the /actuator/env endpoint is enabled and set to writable mode, there are no restrictions on which property keys can be modified or read by authenticated users. This lack of an allow list means that any user with access to this endpoint can potentially manipulate sensitive configuration parameters that control critical aspects of the application's behavior, security settings, database connections, or external service integrations.
From a technical perspective, this vulnerability represents a classic case of insufficient authorization controls and insecure direct object references within the context of dynamic property management. The absence of an allow list implies that the system relies on implicit trust rather than explicit validation of input keys against a predefined set of safe properties. This design oversight allows attackers to overwrite internal configuration values such as security filters, logging levels, or even remote code execution vectors if certain properties are interpreted by underlying frameworks in dangerous ways. For instance, modifying property keys related to serialization mechanisms could lead to deserialization attacks, while altering database connection strings might allow for data exfiltration or denial of service conditions. The vulnerability is particularly severe because it affects a wide range of versions, indicating that the root cause has been present since early iterations of Spring Cloud Commons and persisted through multiple major releases until recent patches were applied.
The operational impact of this flaw can be catastrophic in production environments where sensitive configurations are managed dynamically. An attacker who gains access to the application interface or exploits another vulnerability to reach the actuator endpoint could alter critical system parameters, leading to unauthorized privilege escalation, data breaches, or complete service disruption. Since Spring Cloud is widely used across enterprise infrastructure for managing distributed systems, this vulnerability potentially impacts a vast number of organizations relying on these libraries for their microservices architecture. The lack of an allow list means that even if general access controls are in place, the granularity required to protect specific sensitive properties is missing. This gap allows attackers to perform targeted attacks against configuration-driven behaviors rather than just exploiting code-level bugs, shifting the attack surface from application logic to infrastructure configuration management.
To mitigate this vulnerability, organizations must immediately upgrade Spring Cloud Commons to a version that includes proper allow list enforcement for property keys on writable endpoints. If upgrading is not feasible in the short term, administrators should disable the writable functionality of the /actuator/env endpoint by setting appropriate security properties such as env.enabled=false or restricting access via IP whitelisting and strong authentication mechanisms. Additionally, implementing strict input validation at the gateway level can help filter out malicious requests before they reach the application server. It is also recommended to review all actuator endpoints exposed in production environments and disable any that are not strictly necessary for monitoring purposes. Following industry standards such as CWE-284 which addresses Improper Access Control, and aligning with MITRE ATT&CK techniques related to Configuration Discovery and Modification can help security teams better understand the risk profile associated with this flaw. Regular audits of configuration management practices and continuous integration testing that includes security checks for actuator exposure are essential steps in maintaining a robust defense posture against such vulnerabilities.