CVE-2026-100826 in Firefox
Summary
by MITRE • 09/29/2026
Denial-of-service in the Storage: StorageManager component. This vulnerability was fixed in Firefox ESR 153.4 and Firefox 157.
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Analysis
by VulDB Data Team • 09/29/2026
The identified vulnerability resides within the StorageManager component of the Mozilla Gecko engine, which underpins both Firefox and Firefox Extended Support Release (ESR) browsers. This specific flaw is classified as a denial-of-service condition, indicating that it allows an attacker to disrupt the normal functioning of the browser rather than executing arbitrary code or accessing sensitive data directly through this vector alone. The issue was addressed in Firefox ESR 153.4 and Firefox version 157, marking these releases as the definitive point where the underlying logic errors were corrected by the development team.
From a technical perspective, vulnerabilities within storage management subsystems often stem from improper handling of resource allocation or state transitions during asynchronous operations. In this context, the StorageManager component is responsible for managing persistent data stores such as IndexedDB and local storage on behalf of web applications. When an attacker can trigger specific sequences of API calls or manipulate malformed storage requests, they may cause the browser to enter a loop, exhaust available memory resources, or hang critical threads. This results in the unresponsiveness of the tab or potentially the entire browser process, effectively denying service to legitimate users who rely on the application for productivity or information retrieval.
The operational impact of this vulnerability is primarily centered around availability and user experience degradation. A successful exploitation could lead to a frozen interface where mouse clicks and keyboard inputs are ignored until the process crashes or is manually terminated by the operating system. For enterprise environments deploying Firefox ESR, such instability can disrupt workflows that depend on web-based applications utilizing heavy storage operations. While the immediate effect is non-malicious in terms of data theft, it serves as a potential vector for resource exhaustion attacks if automated scripts are used to repeatedly trigger the flaw across multiple tabs or instances.
In alignment with industry standards, this vulnerability maps closely to CWE-400: Uncontrolled Resource Consumption and potentially CWE-835: Loop with Unreachable Exit Condition depending on the specific internal mechanics of how the hang occurs within the StorageManager logic. From a tactical perspective in threat intelligence frameworks like MITRE ATT&CK, this behavior aligns with techniques related to resource exhaustion or service disruption, although it is typically categorized under initial access vectors only if used as part of a larger campaign involving social engineering to lure users into visiting malicious sites designed to trigger the hang condition.
Mitigation strategies for organizations and individual users involve ensuring that all instances of Firefox are updated to version 157 or later, with ESR users specifically targeting release 153.4 or newer. Since this is a client-side vulnerability triggered by web content, network-level controls such as Web Application Firewalls may offer limited protection unless they can inspect and block specific patterns of storage API abuse, which is often difficult due to the encrypted nature of modern HTTPS traffic and the complexity of legitimate versus malicious usage patterns. Therefore, patch management remains the most effective defense against this class of denial-of-service flaws in browser components.