CVE-2026-59315 in Spring Cloud Config
Summary
by MITRE • 08/27/2026
The Spring Cloud Config Monitor is susceptible to Denial of Service attacks via malicious payloads. Spring Cloud Config 5.0.0 - 5.0.4 Spring Cloud Config 4.3.0 - 4.3.4 Spring Cloud Config 4.0.0 - 4.2.8 Spring Cloud Config 3.1.14 and earlier
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Analysis
by VulDB Data Team • 08/27/2026
The vulnerability identified in the Spring Cloud Config Monitor component represents a significant Denial of Service risk that impacts multiple versions of the framework, specifically affecting releases from version 3.1.14 through 5.0.4 across various minor release branches including 4.x and 5.x series. This flaw is rooted in how the monitor endpoint processes incoming requests, particularly when handling malformed or excessively large payloads designed to exploit resource consumption mechanisms within the application server. The issue arises because the monitoring interface does not adequately validate or limit the size of input data before processing it for configuration refresh events. When an attacker submits a malicious payload characterized by extreme length or complex structure, the system attempts to parse and process this data without sufficient safeguards against memory exhaustion or CPU saturation. This lack of input validation allows external actors to trigger conditions that degrade service availability, effectively rendering the configuration server unable to serve legitimate requests for valid clients seeking updated application configurations.
From a technical perspective, this vulnerability aligns with CWE-400, which describes uncontrolled resource consumption leading to denial of service. The attack vector typically involves sending HTTP POST or PUT requests to the monitor endpoint with payloads that are intentionally oversized or constructed in a way that forces recursive processing loops within the underlying libraries used for parsing configuration data. As the server processes these malicious inputs, it consumes disproportionate amounts of heap memory and CPU cycles compared to standard operations. This behavior can lead to out-of-memory errors where the Java Virtual Machine is forced to terminate due to resource constraints, or it may cause severe latency spikes that make the service effectively unusable for legitimate users. The impact extends beyond simple downtime; in distributed microservices architectures relying on Spring Cloud Config, a compromised configuration server can prevent downstream services from receiving critical updates, thereby disrupting entire application ecosystems and potentially masking other security incidents due to operational paralysis.
The affected versions span several major releases of the framework, indicating that this issue persisted across multiple development cycles before being addressed. Systems running Spring Cloud Config 3.1.14 or earlier are vulnerable as well as those in the 4.x range up to version 4.2.8 and the 5.x series from initial release through 5.0.4. This broad scope suggests that the root cause was embedded deeply within the core monitoring logic rather than being a regression introduced in a single patch cycle. Organizations utilizing these versions must recognize that any deployment exposing the monitor endpoint to untrusted networks or even internal networks without strict access controls is at risk. The vulnerability does not require authentication if the monitor interface is publicly accessible, although it can also be exploited by authenticated users with sufficient privileges to trigger refresh events using malicious payloads.
Mitigation strategies should prioritize immediate patching to the latest stable release of Spring Cloud Config where this issue has been resolved through improved input validation and resource limits. For environments unable to upgrade immediately due to compatibility constraints or testing requirements, defensive measures must be implemented at the network perimeter level. Web Application Firewalls can be configured to inspect HTTP request bodies for excessive length and block requests that exceed predefined thresholds before they reach the application server. Additionally, configuring reverse proxies such as Nginx or Apache to enforce strict limits on client body size provides an effective layer of defense against resource exhaustion attacks. It is also recommended to restrict access to the monitor endpoint by IP address whitelisting if possible, ensuring that only trusted administrative interfaces can trigger configuration refreshes. Regular auditing of exposed endpoints and disabling unnecessary monitoring features in production environments further reduces the attack surface available for exploitation.
In terms of threat intelligence frameworks, this vulnerability maps to MITRE ATT&CK technique T1498, which covers Network Denial of Service via resource exhaustion. Attackers leveraging this flaw aim not to steal data or gain unauthorized access but rather to disrupt operational continuity and create chaos within the infrastructure. The simplicity of the exploit makes it attractive for automated scanning tools that seek quick wins in identifying vulnerable systems. Consequently, security teams should monitor logs for unusual spikes in HTTP request sizes directed at configuration endpoints and implement alerting mechanisms to detect potential abuse patterns early. By combining timely software updates with robust network-level protections and strict access controls, organizations can effectively neutralize this threat vector and maintain the integrity and availability of their cloud-native applications built on Spring Cloud infrastructure.