CVE-2026-113705 in a2a-rs
Summary
by MITRE • 10/22/2026
A vulnerability was determined in a2aproject a2a-rs up to 0.4.3. This issue affects some unknown processing of the file a2a-server/src/error.rs. Executing a manipulation can lead to information exposure through error message. The attack can be executed remotely. This patch is called 713b943af94ab2d521d483b841618b97a2e78a4d. A patch should be applied to remediate this issue.
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Analysis
by VulDB Data Team • 10/22/2026
The vulnerability identified in the a2aproject a2a-rs library, specifically affecting versions up through 0.4.3, represents a significant security flaw rooted in improper error handling within the server-side components of the application. The core technical deficiency lies in the file located at a2a-server/src/error.rs, where the processing logic for generating and returning error responses is inadequately sanitized or structured. This implementation failure allows an attacker to trigger specific conditions that cause the system to expose internal state information through detailed error messages returned to the client. Such behavior indicates a lack of abstraction between internal diagnostic data and user-facing output, which violates fundamental principles of secure coding regarding information leakage prevention.
From an operational perspective, this flaw enables remote attackers to gather sensitive intelligence about the underlying infrastructure without requiring authentication or prior access privileges. By manipulating input parameters to induce errors in specific endpoints, an adversary can receive verbose stack traces, internal file paths, database query structures, or configuration details embedded within the error payload. This information exposure serves as a critical reconnaissance step for subsequent attacks, allowing threat actors to map the application architecture, identify potential injection points, and tailor exploits against known vulnerabilities associated with exposed technologies or versions. The ability to execute this manipulation remotely significantly lowers the barrier to entry for attackers, transforming what might otherwise be a local debugging issue into a widespread remote information disclosure risk.
This vulnerability aligns closely with Common Weakness Enumeration (CWE) category CWE-209, which describes the generation of an error message that includes sensitive information from the software before sending it to the user. It also correlates with CWE-532, concerning exposure of log file information to unauthorized actors if those logs are accessible via the web interface triggered by these errors. In terms of offensive security frameworks, this behavior facilitates reconnaissance activities categorized under MITRE ATT&CK technique T1078, specifically related to gaining access through valid credentials or system misconfigurations that reveal internal details, and more broadly supports information gathering phases such as T1592, which involves collecting target domain network trust relationships. The exposure of technical stack traces can also aid in identifying specific library versions used, linking to enumeration techniques like T1046.
To remediate this issue, it is imperative that developers apply the patch identified by commit hash 713b943af94ab2d521d483b841618b97a2e78a4d as soon as possible for all instances running version 0.4.3 or earlier. Beyond applying the patch, organizations should implement a comprehensive error handling strategy that ensures generic, non-descriptive messages are returned to end-users while detailed diagnostic information is logged securely on the server side only. This approach prevents attackers from leveraging stack traces and internal paths as attack vectors. Additionally, security teams should conduct regular code reviews focusing on exception handling blocks across all API endpoints to ensure no sensitive data leaks through error responses in other parts of the application that may not have been addressed by this specific patch.