CVE-2026-109774 in Firefox
Summary
by MITRE • 10/13/2026
Invalid pointer, undefined behavior in the DOM: Notifications component. This vulnerability was fixed in Firefox 158.
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Analysis
by VulDB Data Team • 10/13/2026
The identified vulnerability resides within the Document Object Model implementation of Mozilla Firefox, specifically affecting the notifications subsystem. This issue is characterized by an invalid memory access pattern that leads to undefined behavior during runtime execution. In complex web browser architectures, the DOM serves as a critical interface between JavaScript code and the underlying rendering engine. When user agents process dynamic content or handle asynchronous events related to system-level features like desktop notifications, they must strictly manage pointer integrity and object lifecycles. The flaw indicates that under specific conditions, likely involving race conditions or improper state management within the notification API handlers, the application attempts to dereference a memory address that is either null, freed, or otherwise invalid. This type of error falls squarely under CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer and potentially CWE-476 NULL Pointer Dereference, depending on the precise nature of the pointer corruption observed during static analysis or fuzzing efforts.
From an operational perspective, undefined behavior in this context poses significant security risks beyond simple application crashes. While immediate exploitation may result in denial of service through process termination, modern memory safety techniques and compiler protections can sometimes mask these issues until they are triggered by crafted inputs designed to manipulate control flow. If the invalid pointer access occurs within a privileged context or allows for arbitrary read/write primitives due to subsequent logic errors, it could potentially lead to remote code execution. Attackers leveraging this vulnerability would likely employ ATT&CK technique T1203 Exploitation for Client Execution, targeting the browser as the initial attack vector. The lack of strict bounds checking in the notification component's internal data structures allows malicious web content or compromised third-party scripts to trigger these invalid accesses by sending specially crafted requests that exploit timing windows or state inconsistencies within the DOM tree manipulation routines.
The resolution of this vulnerability was implemented in Firefox version 158, where developers introduced stricter validation checks and improved memory management protocols for notification-related objects. The fix likely involved adding explicit null checks before pointer dereferencing, implementing safe reference counting mechanisms to prevent use-after-free scenarios, or isolating the notification handling logic within a more sandboxed environment to limit the blast radius of any potential exploitation attempts. For organizations relying on Firefox as their primary web browser, it is imperative to ensure that all client endpoints are updated to version 158 or later to mitigate this risk. Additionally, security teams should monitor for indicators of compromise associated with browser-based exploits and consider deploying content security policies that restrict the execution of untrusted scripts from external domains, thereby reducing the attack surface available to adversaries attempting to trigger such memory corruption vulnerabilities in legacy systems still running older versions.