CVE-2026-92070 in Firefox
Summary
by MITRE • 09/15/2026
Information disclosure in the Networking 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 security issue resides within the networking subsystem of Mozilla Firefox, representing a classic information disclosure vulnerability where sensitive internal state or data is inadvertently exposed to external entities or lower-privilege contexts. Such vulnerabilities typically arise when network requests, responses, or connection metadata are not properly sanitized before being passed to debugging interfaces, error handlers, or cross-origin scripts. In the context of browser architecture, the networking component handles all communication between the user agent and remote servers, making it a critical attack surface for attackers seeking to fingerprint users, bypass security policies, or extract confidential data such as session tokens, headers, or internal IP addresses that should remain opaque to web content.
From a technical perspective, this flaw likely involves improper handling of network response objects or connection states where sensitive details are leaked through console logs, exception messages, or accessible properties on window or document objects. For instance, an attacker might exploit a misconfigured cross-origin resource sharing policy or a race condition in the HTTP stack to trigger error conditions that reveal internal server responses or authentication headers. This type of vulnerability aligns with CWE-200, which classifies information exposure as any situation where sensitive data is made available to unauthorized actors without explicit intent. The exploitation vector often relies on social engineering combined with malicious web content designed to probe the browser's network stack for anomalies that leak internal state.
The operational impact of this vulnerability extends beyond simple data leakage; it can facilitate more sophisticated attacks such as cross-site request forgery amplification, session hijacking, or precise user fingerprinting. By gaining access to detailed networking information, an adversary could determine if a specific service is running on the local network, identify internal infrastructure topology, or confirm the presence of certain authentication mechanisms. This undermines the principle of least privilege and compromises the isolation boundaries that browsers are designed to maintain between web content and system resources. Users relying on Firefox for sensitive operations involving corporate networks or private data could find their security posture weakened if this information is exfiltrated by malicious scripts hosted on untrusted websites.
To mitigate these risks, users must ensure they are running a patched version of the browser, specifically updating to Firefox 156 or Firefox ESR 153.3 as indicated in the advisory. These versions contain code changes that restrict access to sensitive networking data and enforce stricter sanitization protocols for error reporting and debug output. Additionally, organizations should implement content security policies that limit the ability of scripts to interact with network objects excessively and monitor browser telemetry for unusual patterns indicative of exploitation attempts. Regular patch management is essential as vendors continuously refine their attack surfaces against evolving threat landscapes.
This vulnerability maps to MITRE ATT&CK technique T1078, which covers valid accounts and potentially T1539 if it involves stealing credentials through network data leakage. It also relates to CWE-200 for information exposure and CWE-749 for exposing dangerous methods or properties in web applications. Security teams should prioritize the deployment of these updates across all endpoints to close this gap in the browser's defense-in-depth strategy, ensuring that internal networking details remain inaccessible to untrusted third-party content.