CVE-2026-57819 in CXF
Summary
by MITRE • 08/06/2026
Apache CXF allows to set a limit on the number of form parameters in a JAX-RS message via the "maxFormParameterCount" configuration option. However, no default limit is set which may lead to denial of service attacks when processing requests with very large numbers of form parameters. Users are recommended to upgrade to versions 4.2.3 or 4.1.8 or 3.6.12, which fix this issue by using a default limit of 500 parameters.
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Analysis
by VulDB Data Team • 08/06/2026
The Apache CXF framework serves as a comprehensive web services development platform that supports various protocols including JAX-RS for building RESTful applications. When processing form data through JAX-RS endpoints, the framework provides a configuration parameter called "maxFormParameterCount" to control the maximum number of form parameters that can be processed in a single request. This mechanism exists to prevent resource exhaustion attacks targeting the application's parsing capabilities and to ensure predictable memory consumption during request handling.
The vulnerability arises from the absence of a default value for this critical configuration parameter. When administrators fail to explicitly set a limit on form parameters, the system operates with unlimited parameter processing capability. Attackers can exploit this weakness by crafting malicious requests containing an excessive number of form parameters, potentially reaching thousands or even tens of thousands of entries in a single HTTP request. Such attacks can consume significant system resources including memory allocation, CPU cycles, and processing time as the application attempts to parse and handle each parameter individually.
This vulnerability directly maps to CWE-400, which addresses "Uncontrolled Resource Consumption" in software systems. The attack pattern aligns with the broader category of resource exhaustion attacks that target application parsing logic and can be categorized under ATT&CK technique T1499.200, specifically "Resource Exhaustion" targeting application-layer resources. The impact of such denial of service conditions can severely disrupt service availability for legitimate users while potentially allowing attackers to consume system resources at scale.
The remediation strategy involves upgrading to patched versions of Apache CXF where the default limit has been set to 500 form parameters per request. This default value provides a reasonable balance between allowing typical application usage patterns while preventing malicious exploitation through parameter flooding attacks. Organizations should also implement additional monitoring and logging mechanisms to detect unusual spikes in form parameter counts, which could indicate attempted exploitation of this vulnerability.
Security teams should conduct thorough testing of their applications after implementing the upgrade to ensure that legitimate business use cases continue to function properly within the new parameter limits. The configuration should be reviewed to determine if specific applications require higher limits for valid operational purposes, but these adjustments should be made carefully with appropriate monitoring in place. Additionally, organizations should consider implementing rate limiting and input validation at multiple layers of their infrastructure to provide defense-in-depth against similar resource exhaustion vulnerabilities.