CVE-2024-42328 in Zabbix
Summary
by MITRE • 11/27/2024
When the webdriver for the Browser object downloads data from a HTTP server, the data pointer is set to NULL and is allocated only in curl_write_cb when receiving data. If the server's response is an empty document, then wd->data in the code below will remain NULL and an attempt to read from it will result in a crash.
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Analysis
by VulDB Data Team • 10/08/2025
This vulnerability exists within the webdriver implementation of a browser object's HTTP data handling mechanism, specifically when processing responses from HTTP servers through the curl library. The flaw manifests in the data pointer management during HTTP response processing where the data pointer is initially set to NULL and only allocated within the curl_write_cb callback function during data reception. When the HTTP server responds with an empty document, the callback function never executes, leaving the data pointer in a NULL state. This fundamental race condition or improper initialization error creates a critical memory access vulnerability that can lead to application crashes or potential system instability.
The technical implementation of this vulnerability stems from improper null pointer validation in the webdriver's HTTP response handling code. The browser object's webdriver component relies on the curl library for HTTP operations, but fails to properly initialize or validate the data pointer before attempting to access it. According to CWE-476, this represents a null pointer dereference vulnerability where the application attempts to access memory through a null reference. The flaw occurs because the code assumes that data will always be received during the HTTP transaction, failing to account for empty responses from the server. This design oversight creates a condition where the webdriver object maintains a NULL data pointer that is later accessed without proper validation, leading to segmentation faults or access violations.
The operational impact of this vulnerability extends beyond simple application crashes to potentially enable more serious security consequences. An attacker could exploit this weakness by crafting malicious HTTP responses that return empty documents to trigger the null pointer dereference. This type of vulnerability can be leveraged in denial-of-service attacks against applications that utilize the affected webdriver functionality. The vulnerability may also provide a pathway for information disclosure or privilege escalation depending on the application's execution context and memory layout. From an ATT&CK perspective, this vulnerability aligns with T1499.004 for network denial of service and could potentially support techniques for privilege escalation through memory corruption if the application has elevated privileges. The vulnerability affects any system or application that relies on the webdriver's HTTP data handling capabilities, particularly those implementing automated browser testing or web scraping functionalities.
Mitigation strategies for this vulnerability require immediate code-level fixes to ensure proper null pointer validation before data access operations. Developers should implement comprehensive input validation that checks for NULL data pointers before attempting to read from them, ensuring that all code paths properly initialize or validate memory references. The fix should involve adding explicit NULL checks in the webdriver's response handling logic before accessing wd->data, implementing proper error handling for empty responses, and ensuring that memory allocation occurs regardless of response content. Additionally, implementing proper defensive programming practices including bounds checking, memory initialization, and input sanitization can prevent similar issues. Organizations should also consider implementing runtime protections such as address space layout randomization and stack canaries, along with regular security audits of HTTP handling components to identify similar race conditions or improper memory management patterns that could lead to similar vulnerabilities.