CVE-2026-92044 in Firefox
Summary
by MITRE • 09/15/2026
Information disclosure in the Networking: HTTP component. This vulnerability was fixed in Firefox 156 and Firefox ESR 153.3.
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Analysis
by VulDB Data Team • 09/15/2026
The identified vulnerability resides within the networking subsystem of Mozilla Firefox, specifically affecting its Hypertext Transfer Protocol (HTTP) implementation. As a web browser, Firefox relies heavily on robust HTTP handling to fetch resources, manage sessions, and render dynamic content from remote servers. The flaw involves an improper exposure of internal state or sensitive data during the processing of HTTP requests and responses. This type of information disclosure typically arises when the application fails to properly sanitize output or restricts access to debugging variables that are inadvertently exposed to external parties through network packets or error messages generated by the browser's networking stack.
From a technical perspective, this vulnerability likely stems from an oversight in how the HTTP component handles specific edge cases during connection establishment, header parsing, or response decoding. When certain malformed or specially crafted HTTP headers are processed, the application may leak internal memory contents, session identifiers, authentication tokens, or other sensitive contextual information that should remain private to the client-side execution environment. This leakage can occur through verbose error reporting mechanisms or by failing to clear temporary buffers before reusing them for subsequent network operations. The presence of such a flaw indicates a gap in input validation and output encoding practices within the HTTP module's codebase, allowing an attacker who is positioned on the same network path as the victim to intercept these disclosures.
The operational impact of this vulnerability centers around the potential compromise of user privacy and session integrity. An adversary capable of performing man-in-the-middle attacks or monitoring local network traffic could exploit this flaw to extract sensitive data that was not intended for transmission over the wire. This might include cookies containing session tokens, which could lead to account takeover if intercepted and replayed before expiration. Additionally, exposure of internal browser state can aid in fingerprinting efforts, allowing attackers to identify specific versions or configurations of Firefox being used by a target, thereby facilitating more targeted subsequent attacks against known vulnerabilities in that specific build. In enterprise environments where sensitive corporate data is accessed via web applications, such leaks could result in the unauthorized disclosure of proprietary information or credentials stored within browser storage mechanisms.
To mitigate this risk, it is imperative to apply the security patches provided by Mozilla immediately. The vulnerability has been addressed in Firefox version 156 and Firefox Extended Support Release (ESR) version 153.3. Organizations should ensure that their endpoint management systems are configured to automatically deploy these updates across all workstations running affected versions of the browser. For users unable to update immediately, employing network-level security controls such as TLS inspection with strict certificate validation can help mitigate some aspects of man-in-the-middle exploitation, although it does not fully resolve the underlying application flaw. Furthermore, enabling Content Security Policy (CSP) headers on web applications accessed via Firefox can provide an additional layer of defense by restricting how resources are loaded and reducing the attack surface for cross-site scripting or data exfiltration attempts that might leverage this disclosure.
This vulnerability aligns with Common Weakness Enumeration category CWE-200, which classifies Information Exposure as a flaw where sensitive information is disclosed to unauthorized actors without explicit intent. In terms of offensive security frameworks, it relates to ATT&CK technique T1537, Transfer Data to Cloud Account, if the leaked data facilitates exfiltration, or more broadly to reconnaissance activities that gather intelligence about target systems and software versions. Maintaining up-to-date browser installations is the most effective defense against such implementation flaws in core networking components, as vendors continuously refine their HTTP parsers to close these gaps in logic and memory management.