CVE-2026-118272 in a2ui
Summary
by MITRE • 10/28/2026
A vulnerability was detected in a2ui-project a2ui up to 0.10.6. Affected is the function DataContext.dispatchExpressionError of the file renderers/web_core/src/v0_9/rendering/data-context.ts of the component Error Handler. Performing a manipulation results in information exposure through error message. It is possible to initiate the attack remotely. The exploit is now public and may be used. The patch is named 8f149a1c7b0ce1fa8e93ac3adfa5fda960faeb01. It is suggested to install a patch to address this issue.
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Analysis
by VulDB Data Team • 10/28/2026
The vulnerability identified in the a2ui-project, specifically within versions up to 0.10.6, centers on an improper handling of error conditions within the web rendering engine. The core technical flaw resides in the DataContext.dispatchExpressionError function located in the file renderers/web_core/src/v0_9/rendering/data-context.ts. This component is responsible for managing and displaying errors that occur during data binding or expression evaluation processes. When a manipulated input triggers an internal error, the system fails to sanitize or abstract the resulting exception details before presenting them to the client-side environment. Instead of returning a generic or user-friendly message, the application exposes raw stack traces, variable states, or internal configuration paths embedded within the error payload. This behavior constitutes a classic case of information exposure through improper error handling, allowing an attacker to glean sensitive architectural insights that can facilitate further exploitation attempts against the underlying infrastructure.
From a technical perspective, this flaw aligns with CWE-209: Generation of Error Message Containing Sensitive Information and CWE-755: Improper Handling of Unexpected or Unusual Input. The vulnerability is particularly dangerous because it enables remote information disclosure without requiring authentication in many configurations, as the error state can often be triggered by malformed API requests or specially crafted user inputs within the application interface. By analyzing these verbose error messages, an attacker can map out the internal directory structure, identify specific library versions used in the backend stack, and potentially discover other unhandled edge cases that could lead to more severe vulnerabilities such as remote code execution or SQL injection if similar patterns exist elsewhere in the codebase. The fact that this exploit is now public significantly lowers the barrier for entry, allowing less sophisticated threat actors to leverage automated tools to scan for instances of a2ui and extract these sensitive details systematically.
The operational impact of this vulnerability extends beyond mere data leakage. While information disclosure itself may not directly compromise confidentiality or integrity in all contexts, it serves as a critical reconnaissance phase that aids attackers in planning more targeted attacks. For organizations relying on a2ui for dynamic web content rendering, the exposure of internal error states can reveal proprietary logic flows and third-party dependencies, thereby increasing the attack surface. Furthermore, if these errors are logged server-side with high verbosity, they may also contribute to log injection vulnerabilities or provide clues for denial-of-service attacks by forcing the application into repeated error-handling loops. The availability of a public exploit means that automated scanners and malicious actors can actively probe networks hosting affected versions, leading to potential compliance violations regarding data protection standards if sensitive internal information is deemed part of protected datasets depending on jurisdictional regulations like GDPR or HIPAA.
To mitigate this risk, immediate action is required to update the a2ui library to version 0.10.7 or later, where the patch identified as commit hash 8f149a1c7b0ce1fa8e93ac3adfa5fda960faeb01 has been applied. This patch modifies the error handling logic within the DataContext class to ensure that only sanitized, non-sensitive information is returned to the client side during expression evaluation failures. In addition to applying the software update, organizations should implement robust input validation and output encoding strategies across all web applications using this framework. It is also recommended to configure application-level logging policies to prevent sensitive stack traces from being written to accessible log files or displayed in production environments. Adopting a defense-in-depth approach by placing reverse proxies or Web Application Firewalls (WAFs) in front of the application can further help filter out malformed requests that trigger these error states, thereby reducing the likelihood of successful exploitation even if other vulnerabilities exist within the stack.