CVE-2026-114459 in Apache
Summary
by MITRE • 10/22/2026
A flaw was found in mod_qos. When inspecting HTTP response bodies, improper boundary checking can cause the module to read memory outside allocated buffer boundaries. An unauthenticated remote attacker can exploit this vulnerability by triggering specifically crafted server responses, causing an Apache worker process to crash and resulting in a Denial of Service (DoS).
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Analysis
by VulDB Data Team • 10/22/2026
The mod_qos module for Apache HTTP Server contains a critical out-of-bounds read vulnerability that arises from insufficient validation during the inspection of HTTP response bodies. This flaw is rooted in improper boundary checking within the code logic responsible for parsing and analyzing incoming server responses. When the module processes these responses, it fails to correctly verify whether the data being accessed exists within the allocated memory buffer limits. Consequently, if an attacker can manipulate or trigger specific crafted server responses that exploit this logical gap, the application will attempt to read from memory addresses beyond its designated allocation space. This type of error is a classic example of CWE-125, which describes out-of-bounds read vulnerabilities where software reads data past the end or before the beginning of the intended buffer.
The operational impact of this vulnerability is primarily focused on service availability rather than confidentiality or integrity in most immediate scenarios. Because the flaw leads to an invalid memory access within a worker process handling HTTP requests, it typically results in the abrupt termination or crash of that specific Apache worker thread. In environments where mod_qos is deployed to manage traffic and prevent overload, such crashes can cascade if not properly isolated by the server configuration, potentially leading to a complete Denial of Service condition for users attempting to access the web service. An unauthenticated remote attacker does not need valid credentials to exploit this issue; they simply need to be able to send requests that trigger the specific response patterns causing the buffer overflow read error. This aligns with ATT&CK technique T1498, Network Denial of Service, as it allows an adversary to disrupt service availability through resource exhaustion or process termination.
Mitigation strategies for this vulnerability involve immediate patching of the mod_qos module to a version that includes fixes for these boundary checks. Administrators should verify their current configuration and update the software components accordingly. In cases where updating is not immediately feasible, deploying a Web Application Firewall may help by filtering out malformed HTTP responses or requests that exhibit patterns consistent with this exploitation vector. Additionally, configuring Apache worker processes with appropriate limits can help contain the impact of such crashes, ensuring that one compromised process does not take down the entire server instance. Regular security audits and monitoring for unusual spikes in error logs related to mod_qos can also aid in early detection of attempted exploits or ongoing attacks targeting this specific weakness.