CVE-2026-92077 in Firefox
Summary
by MITRE • 09/15/2026
Denial-of-service in the SVG component. This vulnerability was fixed in Firefox 156 and Firefox ESR 153.3.
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Analysis
by VulDB Data Team • 09/15/2026
The identified vulnerability represents a critical denial of service condition within the Scalable Vector Graphics rendering engine, specifically affecting the processing logic for SVG content. Denial of service vulnerabilities occur when an application fails to properly handle unexpected or malformed input, leading to resource exhaustion, infinite loops, or crashes that render the software unusable. In this specific instance, the flaw resides in how Firefox parses and renders complex or maliciously crafted SVG files. When a user navigates to a webpage containing such content, or opens a local file with these characteristics, the browser's rendering engine enters an unstable state. This instability typically manifests as high CPU usage that prevents other processes from executing effectively, freezing the graphical interface entirely, or causing the application process to terminate unexpectedly without warning.
From a technical perspective, this issue aligns closely with CWE-400, which describes conditions where resources are not properly controlled, leading to exhaustion of those resources such as memory, CPU cycles, or disk space. The vulnerability likely stems from inefficient algorithmic handling of specific SVG path commands, nested elements, or animation properties that trigger recursive processing loops or excessive computational overhead during the layout and paint phases. Because SVG is an XML-based format used for defining two-dimensional vector graphics, its complexity allows attackers to construct files with deeply nested structures or repetitive patterns designed to exploit parsing inefficiencies. The browser must decode these instructions in real-time while maintaining responsiveness, a balance that this vulnerability disrupts by consuming excessive system resources during the rendering pipeline execution.
The operational impact of this flaw is significant for both individual users and enterprise environments relying on Firefox as their primary web client. For end-users, encountering such content results in immediate service disruption where the browser becomes unresponsive, requiring manual termination via task managers or force-quitting applications to restore system functionality. This not only degrades user experience but also poses a risk of data loss if unsaved work is present in other open tabs or documents. In enterprise settings, this vulnerability can be weaponized for targeted attacks against employees who may receive malicious emails containing links to compromised websites hosting the exploit code. The resulting instability disrupts productivity and increases help desk support tickets related to browser crashes and system freezes.
Mitigation strategies primarily involve applying the vendor-provided patches that address these parsing inefficiencies. Users must ensure they are running Firefox version 156 or later, as well as Firefox ESR 153.3 or newer versions of the Extended Support Release channel. These updates contain code changes that optimize resource management and add safeguards against infinite loops during SVG rendering. Until patches can be applied in environments with strict update cycles, administrators should consider implementing network-level filtering to block access to untrusted domains known for hosting malicious content. Additionally, enabling browser security features such as sandboxing helps isolate the renderer process from critical system resources, limiting the blast radius of any potential exploitation attempts even if a vulnerability is present.
This incident underscores the importance of continuous patch management and secure coding practices in web browsers that handle complex markup languages. The classification of this flaw highlights ongoing challenges in balancing performance with security when processing dynamic content. By addressing these issues through timely updates, organizations can maintain system integrity and ensure consistent availability for users relying on modern web technologies.