CVE-2026-92025 in Firefox
Summary
by MITRE • 09/15/2026
Use-after-free in the DOM: Navigation component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, and Firefox ESR 153.3.
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Analysis
by VulDB Data Team • 09/15/2026
The identified vulnerability represents a critical memory management error within the Document Object Model navigation component of Mozilla Firefox browsers. Specifically classified as an use-after-free condition, this flaw occurs when the application continues to reference a memory block after it has been deallocated or freed by the system. In the context of DOM manipulation and browser navigation events, such errors typically arise from complex interactions between JavaScript execution contexts, event handlers, and internal C++ object lifecycles. When an attacker can trigger specific sequences of page navigations or dynamic content updates, they may cause the underlying memory to be released while a pointer or reference to that memory remains active in another part of the browser process. This creates a window where the application attempts to read from or write to invalid memory addresses, leading to undefined behavior and potential system compromise.
From a technical perspective, use-after-free vulnerabilities are particularly dangerous because they allow for arbitrary code execution under certain conditions. If an attacker can control the data that is written into the freed memory region before it is reallocated for another purpose, they may achieve heap spraying or structure corruption techniques. This can lead to the execution of malicious shellcode within the context of the browser process. The navigation component is a high-value target because it handles frequent user interactions and complex state changes, increasing the likelihood that an attacker can manipulate timing conditions to exploit this race condition or logical error in memory management. Such vulnerabilities often require sophisticated exploitation techniques involving heap grooming to ensure predictable memory layouts, but successful exploitation grants full control over the compromised browser instance.
The operational impact of this vulnerability is severe, as it directly affects user security and data integrity. A successfully exploited use-after-free can allow a remote attacker to execute arbitrary code on the victim's machine by simply convincing them to visit a maliciously crafted webpage or click a specially designed link. This could result in the installation of malware, theft of sensitive credentials stored within the browser session, hijacking of active sessions through cookie theft, or further lateral movement if the user is part of an enterprise network. The risk is exacerbated by the fact that modern browsers run multiple processes for security isolation; however, breaking out of a renderer process to gain code execution in a more privileged process remains a primary goal for attackers leveraging such memory corruption flaws.
This vulnerability aligns with CWE-416, which defines use-after-free as an error where software uses memory after it has been freed, and is often associated with CWE-362 regarding concurrent execution race conditions if the issue stems from improper synchronization of resource access. In terms of offensive security frameworks, this flaw facilitates techniques categorized under MITRE ATT&CK T1059 Command and Scripting Interpreter or potentially T1204 User Execution depending on how the initial payload is delivered. The exploitation path typically involves crafting a malicious HTML page that triggers specific DOM events to induce the memory state inconsistency required for the exploit chain.
Mitigation strategies primarily rely on applying the vendor-provided patches released in Firefox version 156, as well as the extended support release versions 115.41, 140.16, and 153.3. Organizations should prioritize updating all endpoints running affected browser versions to ensure that the underlying memory management logic is corrected by Mozilla engineers who likely implemented stricter pointer validation or smart pointers to prevent dangling references. Additionally, users can employ exploit mitigation technologies such as Address Space Layout Randomization (ASLR) and Data Execution Prevention (DEP), although these are defensive layers rather than fixes for the root cause. Security teams should also monitor for indicators of compromise related to browser-based exploits, including unusual network connections from browser processes or unexpected process spawns following web browsing activity, to detect potential exploitation attempts in real-time before patches can be deployed across all systems.