CVE-2023-4540 in lua-http
Summary
by MITRE • 09/05/2023
Improper Handling of Exceptional Conditions vulnerability in Daurnimator HTTP Library for Lua allows Excessive Allocation.This issue affects HTTP Library for Lua: before commit ddab283.
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Analysis
by VulDB Data Team • 08/24/2025
The CVE-2023-4540 vulnerability represents a critical improper handling of exceptional conditions within the Daurnimator HTTP Library for Lua, specifically manifesting as excessive memory allocation during error processing scenarios. This vulnerability exists in versions of the library prior to commit ddab283 and fundamentally stems from inadequate exception handling mechanisms that fail to properly manage resource allocation when unexpected conditions occur during HTTP request processing. The flaw allows malicious actors to exploit the library's response to malformed or exceptional network conditions by triggering excessive memory consumption patterns that can lead to resource exhaustion and potential denial of service.
The technical implementation of this vulnerability involves the library's failure to properly constrain memory allocation during exception handling routines. When the HTTP library encounters malformed responses, connection failures, or other exceptional network conditions, the improper exception handling causes the system to allocate increasingly larger memory buffers without adequate bounds checking or resource limits. This behavior aligns with CWE-704, which categorizes improper handling of exceptional conditions as a fundamental flaw in resource management. The vulnerability specifically targets the library's internal memory allocation algorithms that are designed to handle dynamic response sizes but fail to implement proper safeguards against maliciously crafted inputs that could cause unbounded growth in memory consumption.
Operational impact of this vulnerability extends beyond simple denial of service scenarios to potentially compromise entire application availability and system stability. When exploited, the excessive allocation behavior can cause applications using the affected HTTP library to consume all available system memory, leading to application crashes, system instability, and cascading failures across dependent services. The vulnerability is particularly dangerous in high-throughput environments or applications that process large volumes of HTTP requests, as the memory exhaustion can occur rapidly and without obvious warning signs. From an attacker perspective, this vulnerability enables resource exhaustion attacks that can be executed with minimal privileges and require no specialized knowledge of the underlying system architecture.
Mitigation strategies for CVE-2023-4540 should focus on immediate library updates to versions that include the fix implemented in commit ddab283, which properly addresses the exception handling and memory allocation constraints. Organizations should also implement monitoring and alerting mechanisms to detect unusual memory consumption patterns that may indicate exploitation attempts. Additional defensive measures include implementing resource limits on application processes, deploying input validation layers, and conducting thorough security assessments of all applications that utilize the affected library. The vulnerability demonstrates the importance of proper resource management in network libraries and aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion. System administrators should also consider implementing network segmentation and rate limiting to reduce the impact of potential exploitation attempts and prevent the vulnerability from being used as a vector for broader network compromise.