CVE-2026-117952 in Firefox
Summary
by MITRE • 10/27/2026
Uninitialized memory in the Networking component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, and Firefox ESR 153.6.
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Analysis
by VulDB Data Team • 10/27/2026
The identified vulnerability resides within the networking subsystem of Mozilla Firefox, specifically involving improper initialization of memory structures prior to their use by application logic. This class of defect is categorized under CWE-908, which denotes the use of uninitialized resource or variable, a common source of instability and potential security breaches in complex software systems such as web browsers. The root cause typically stems from code paths where variables are declared but not assigned default values before being accessed for critical network operations, leading to unpredictable behavior depending on whatever data previously occupied that memory location.
From an operational perspective, the exploitation of this uninitialized memory flaw can lead to a variety of adverse outcomes ranging from information disclosure to remote code execution. If sensitive cryptographic keys or session tokens are stored in these uninitialized regions and subsequently read without proper validation, attackers may leverage this leakage to hijack user sessions or decrypt communications. Furthermore, if the uninitialized data influences control flow decisions within the networking stack, it could potentially allow an attacker to manipulate packet processing logic, leading to denial of service conditions through crashes or more sophisticated attacks that exploit memory corruption primitives for arbitrary code execution.
The technical impact is compounded by the fact that network components often handle untrusted input from remote servers and web pages. An adversary hosting a malicious website could craft specific requests designed to trigger this uninitialized access pattern during connection establishment, header parsing, or response handling phases. This aligns with MITRE ATT&CK techniques related to initial access and defense evasion, where attackers seek to exploit software flaws to gain footholds in target environments while avoiding detection through standard security controls that may not monitor low-level memory state anomalies effectively.
Mitigation strategies primarily involve the immediate application of vendor-provided patches, as demonstrated by the fixes included in Firefox version 159, Firefox Extended Support Release (ESR) version 115.44, and ESR version 153.6. Organizations relying on these browser versions must ensure their update mechanisms are configured to deploy these security builds promptly across all endpoints. For development teams maintaining similar networking libraries, the remediation requires rigorous code review practices focused on variable initialization states, particularly in high-throughput or complex state-machine implementations. Static analysis tools should be employed to detect uninitialized variable usage patterns, and dynamic testing methods such as fuzzing can help identify edge cases where memory is accessed before being properly set by developers.