CVE-2026-109768 in Firefox
Summary
by MITRE • 10/13/2026
Denial-of-service in the Site Reports 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 Site Reports component of Mozilla Firefox, specifically manifesting as a denial-of-service condition that can be triggered by maliciously crafted web content or network interactions targeting this specific subsystem. The root cause typically involves improper handling of input data or resource management failures during the generation and processing of site-specific telemetry or diagnostic reports. When an attacker crafts a payload designed to exploit these logic errors, it forces the browser engine into an unstable state, leading to excessive memory consumption, infinite loops, or unhandled exceptions that crash the application process. This type of flaw is categorized under CWE-400, which covers Uncontrolled Resource Consumption, as the vulnerability allows an external entity to exhaust system resources available to the Firefox instance without requiring authentication or privileged access from the user perspective.
From a tactical standpoint, this vulnerability aligns with ATT&CK technique T1499, Endpoint Denial of Service, where the adversary's objective is to degrade or disrupt the availability of computing resources rather than compromise confidentiality or integrity. In the context of web browsers, such vulnerabilities are particularly dangerous because they can be triggered remotely via standard HTTP requests embedded in malicious websites or through compromised third-party scripts. The operational impact includes a complete loss of browser functionality for the affected user session, potentially leading to data loss if unsaved work is present and requiring manual intervention to restart the application. Furthermore, repeated exploitation attempts could contribute to broader service degradation if multiple instances are targeted simultaneously, although this is less common in client-side applications compared to server-side environments.
The resolution of this issue was implemented in Firefox version 158 through rigorous code auditing and patching efforts that addressed the underlying logic errors within the Site Reports module. The fix likely involved adding strict input validation checks, implementing resource limits to prevent runaway processes, or correcting error handling routines to ensure graceful degradation rather than catastrophic failure when anomalous data is encountered. Security researchers and developers emphasize that such patches are critical for maintaining the stability of the browser ecosystem, as even minor flaws in reporting mechanisms can be weaponized by threat actors seeking to disrupt user productivity or create noise during more sophisticated attacks.
To mitigate the risks associated with similar vulnerabilities in legacy systems or other software components, organizations should prioritize regular patch management cycles and ensure that all endpoints are updated to include the latest security fixes provided by vendors. Additionally, deploying browser isolation technologies or sandboxing solutions can limit the blast radius of any successful exploitation attempt, preventing a compromised renderer process from affecting critical system resources. Continuous monitoring for unusual resource usage patterns within browser processes can also serve as an early detection mechanism for denial-of-service attempts, allowing administrators to respond before significant disruption occurs.