CVE-2026-59305 in Spring Cloud Stream
Summary
by MITRE • 08/27/2026
Partition interceptor may be improperly added while sending message. Spring Cloud Stream 5.0.0 - 5.0.2 Spring Cloud Stream 4.3.0 - 4.3.3 Spring Cloud Stream 4.2.0 - 4.2.6
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Analysis
by VulDB Data Team • 08/27/2026
The vulnerability identified in the specified versions of Spring Cloud Stream, ranging from version 4.2.0 through 5.0.2 and specifically affecting patch releases within those series, centers on an improper handling of partition interceptors during message transmission operations. This flaw represents a logic error where the framework fails to correctly associate or apply partition interceptor configurations when messages are being routed to specific partitions in downstream systems such as Apache Kafka or RabbitMQ. In distributed messaging architectures, partitioning is critical for load balancing and parallel processing, ensuring that related data items are processed by the same consumer instance while unrelated items can be handled concurrently. When a partition interceptor is improperly added or applied during this process, it disrupts the deterministic routing logic intended to maintain message ordering and consistency within specific partitions.
From a technical perspective, this issue stems from how the framework manages the lifecycle of interceptors in relation to the producer template's execution flow. The vulnerability allows for scenarios where either no interceptor is applied when one should be, or an incorrect interceptor context is used, leading to unpredictable partition assignment behavior. This can result in messages being sent to unintended partitions, which breaks the guarantee that keys mapping to the same logical group will always reside on the same physical partition. Such inconsistency undermines the reliability of stateful processing applications that depend on strict ordering and grouping semantics provided by message brokers. The flaw is particularly insidious because it may not cause immediate application crashes but rather introduces subtle data integrity issues or performance degradation due to unbalanced load distribution across consumer instances.
The operational impact of this vulnerability extends beyond mere configuration errors, affecting the core reliability guarantees expected from enterprise-grade messaging systems. Applications relying on Spring Cloud Stream for event-driven architectures may experience message reordering, where subsequent messages in a sequence are processed out of order because they landed on different partitions than their predecessors. This can lead to business logic failures, such as incorrect financial calculations or inconsistent user states in real-time applications. Furthermore, the improper interceptor handling can cause increased latency and resource contention if partition distribution becomes skewed, forcing certain consumer instances to handle disproportionately high volumes of traffic while others remain underutilized. In security-sensitive contexts, this unpredictability could potentially be leveraged for denial-of-service conditions by manipulating message keys to overwhelm specific nodes in a cluster.
This vulnerability aligns with CWE-841, Improper Enforcement of Behavioral Workflow, as the application fails to enforce the correct sequence or method for applying partitioning logic during message transmission. It also relates to CWE-20, Improper Input Validation, since the framework does not adequately validate that interceptor configurations are correctly bound and executed within the producer context before dispatching messages. From an ATT&CK perspective, while this is primarily a reliability issue rather than a direct exploitation vector for unauthorized access, it falls under techniques related to resource exhaustion or impact on availability if exploited at scale through malicious key manipulation. The lack of proper enforcement allows attackers who can influence message keys to disrupt service continuity and data consistency within the microservices ecosystem.
Mitigation strategies require immediate upgrading to patched versions outside the affected ranges, specifically ensuring that Spring Cloud Stream is updated beyond version 5.0.2 or 4.3.3 depending on the major release line in use. For organizations unable to upgrade immediately due to compatibility constraints with other dependent libraries, implementing custom producer interceptors that explicitly manage partition assignment logic can serve as a temporary workaround. Developers should review their message production code to ensure that any manual interceptor registrations are correctly scoped and do not interfere with the framework's default partitioning mechanisms. Additionally, rigorous testing of message ordering guarantees in staging environments using load simulation tools is recommended to detect any anomalies in partition distribution before deploying changes to production systems. Regular audits of configuration files for Spring Cloud Stream components can help identify misconfigurations that might exacerbate this vulnerability under high-throughput conditions.