CVE-2026-117507 in a2a-java
Summary
by MITRE • 10/27/2026
A security vulnerability has been detected in a2aproject a2a-java up to 1.2.0.Final. This impacts the function TaskManager.saveTaskEvent. The manipulation leads to race condition. The attack may be initiated remotely. Upgrading to version 1.3.0.Final will fix this issue. The identifier of the patch is 6b8e1e085c35e970ef0048901cd25850e4791ec2. The affected component should be upgraded.
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Analysis
by VulDB Data Team • 10/27/2026
The a2a-java library, specifically versions up to 1.2.0.Final of the a2aproject suite, contains a critical concurrency flaw within its TaskManager.saveTaskEvent function that exposes systems to race condition vulnerabilities. This issue arises from insufficient synchronization mechanisms when handling concurrent access to shared task state data structures. In multi-threaded environments or remote service calls where multiple requests may attempt to save or update task events simultaneously, the lack of proper locking or atomic operations allows for non-deterministic behavior. An attacker who can initiate interactions with this component remotely can exploit these timing windows to manipulate the internal state of tasks in unintended ways. This type of vulnerability is commonly categorized under CWE-362, which defines concurrent execution using shared resources with inadequate synchronization as a distinct class of software weakness. The absence of robust thread safety measures means that operations intended to be atomic may execute out of order or overwrite each other's changes, leading to data corruption or inconsistent application states.
The operational impact of this race condition is significant for any system relying on the integrity and consistency of task management workflows within the a2a-java framework. Since the vulnerability can be triggered remotely, it presents an attack vector that does not require local access or prior authentication in some configurations, depending on how the TaskManager endpoints are exposed. An adversary could potentially cause denial of service by corrupting critical task data, leading to system instability or crashes. Furthermore, if business logic depends on the correct sequence and state of tasks for security decisions such as authorization checks or audit logging, a race condition could allow an attacker to bypass these controls. For instance, by manipulating the timing of event saves, an actor might create a scenario where a task is marked as completed before necessary validation steps are fully processed, effectively circumventing intended security boundaries. This aligns with ATT&CK techniques related to resource hijacking or defense evasion through state manipulation, although it primarily falls under exploitation for availability and integrity compromise rather than direct privilege escalation unless combined with other flaws.
To mitigate this risk, immediate action is required to upgrade the affected component to version 1.3.0.Final of a2a-java. This release incorporates specific patches designed to address the concurrency issues identified in earlier versions. The patch identifier for this fix is 6b8e1e085c35e970ef0048901cd25850e4791ec2, which introduces proper synchronization primitives such as locks or atomic variables to ensure that the saveTaskEvent operation completes atomically. Organizations should verify their dependency management configurations to enforce this minimum version and conduct regression testing to confirm that the updated concurrency controls do not introduce performance bottlenecks in high-throughput scenarios. Additionally, developers reviewing codebases using older versions of a2a-java should audit other areas for similar synchronization gaps, as race conditions often indicate broader architectural weaknesses in thread safety practices. Implementing comprehensive logging around task state changes can also aid in detecting any residual anomalies during the transition period until all instances are fully upgraded and monitored.