CVE-2026-92036 in Firefox
Summary
by MITRE • 09/15/2026
Incorrect boundary conditions in the Networking: HTTP component. This vulnerability was fixed in Firefox 156.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 09/15/2026
The identified vulnerability resides within the Hypertext Transfer Protocol implementation of Mozilla Firefox, specifically affecting the networking layer responsible for parsing and handling HTTP traffic. The core technical flaw stems from incorrect boundary condition checks during the processing of incoming or outgoing HTTP requests and responses. In complex protocol implementations like HTTP/1.1 or HTTP/2, precise validation of headers, body lengths, and state transitions is critical to maintaining memory integrity and logical consistency. When these boundaries are not strictly enforced, the application may misinterpret data structures, leading to out-of-bounds reads or writes. This type of error typically occurs when the software fails to correctly calculate buffer sizes relative to the actual content length specified in HTTP headers, allowing an attacker to craft a maliciously formatted request that exceeds expected limits without triggering appropriate exception handling mechanisms.
From a security architecture perspective, this flaw aligns with CWE-125, Out-of-bounds Read, or potentially CWE-787, Out-of-bounds Write, depending on the specific memory operation affected by the boundary miscalculation. These weaknesses are particularly dangerous in network-facing components because they can be triggered remotely without user interaction beyond visiting a maliciously crafted webpage or being subjected to a man-in-the-middle attack that modifies HTTP traffic. The vulnerability exploits the trust placed in the browser's ability to safely parse standard web protocols, turning a routine data exchange into an opportunity for memory corruption. Such conditions often lead to crashes, which can be leveraged for denial-of-service attacks, but more critically, they provide a pathway for arbitrary code execution if the memory layout allows overwriting control flow pointers or function addresses.
The operational impact of this vulnerability is significant due to its location in the core networking stack. An attacker could potentially exploit this flaw by hosting a malicious website that sends specially crafted HTTP requests designed to trigger the incorrect boundary conditions. Successful exploitation could result in the compromise of user data, including session cookies and authentication tokens stored within the browser profile. Furthermore, memory corruption vulnerabilities are frequently used as initial access vectors for more complex attack chains involving sandbox escape techniques. By breaking out of the browser's security boundaries through a heap or stack overflow facilitated by this HTTP parsing error, an attacker could gain execution privileges at the operating system level, effectively taking control of the victim's machine. This aligns with MITRE ATT&CK technique T1203, Exploitation for Client Execution, where vulnerabilities in client-side software are leveraged to deploy malware or establish persistence on the target system.
Mitigation strategies primarily involve applying the vendor-provided patch released in Firefox version 156, which corrects the boundary validation logic within the HTTP component. Organizations and individual users should ensure that their browsers are updated immediately to close this attack surface. In environments where immediate patching is not feasible, network-level controls such as Web Application Firewalls can be configured to inspect and sanitize HTTP traffic for anomalous header lengths or malformed request structures before they reach the client application. Additionally, enabling strict Content Security Policy headers on web applications served by vulnerable browsers can help mitigate potential downstream impacts by restricting how resources are loaded and executed, thereby reducing the effectiveness of any exploit that might leverage this vulnerability for further malicious activity. Regular security audits focusing on protocol parsing logic in network libraries remain essential to prevent similar boundary condition errors from being introduced during future development cycles.