CVE-2026-92046 in Firefox
Summary
by MITRE • 09/15/2026
Use-after-free in the Graphics 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 security flaw represents a critical memory management error classified as an out-of-bounds write, specifically manifesting through a use-after-free condition within the browser's Graphics subsystem. This type of vulnerability arises when the application attempts to access or modify memory that has already been deallocated by the system. In the context of modern web browsers like Firefox, the graphics component is responsible for rendering visual elements such as images, videos, and complex CSS layouts using hardware acceleration APIs. When a pointer referencing freed memory is not properly nullified or updated after the underlying resource is released, subsequent operations may inadvertently write data to arbitrary locations in the process's address space. This scenario creates a dangerous race condition where the timing of garbage collection versus rendering updates determines whether malicious code can exploit the stale reference.
From an operational perspective, this vulnerability poses severe risks including remote code execution and denial of service attacks. An attacker could craft a specially designed webpage containing malicious JavaScript or embedded media that triggers the premature deallocation of graphics resources while retaining references to them. By carefully controlling memory layout through heap spraying techniques, it is possible to place sensitive data or executable shellcode in the freed memory region. When the browser subsequently performs a write operation via the dangling pointer, the attacker gains control over program execution flow. This can lead to full system compromise if exploited successfully, allowing unauthorized access to user credentials, session tokens, and private files stored on the local machine.
The technical classification of this flaw aligns with Common Weakness Enumeration identifier CWE-416, which describes use-after-free errors resulting from improper memory management practices. In terms of offensive security frameworks, such an exploit typically maps to MITRE ATT&CK technique T1203, specifically the exploitation of vulnerabilities for initial access or execution phases. The graphics stack is a frequent target because it handles untrusted input from web content and operates with high privileges relative to other browser processes. The complexity of managing asynchronous rendering tasks increases the likelihood of timing-related bugs where memory lifecycle management fails under specific concurrent conditions.
Mitigation strategies primarily involve applying the vendor-provided patch released in Firefox version 156 and Firefox Extended Support Release version 153.3. These updates include rigorous validation checks to ensure that pointers are invalidated immediately after deallocation, preventing any subsequent access attempts from succeeding without triggering a crash or security exception rather than allowing silent corruption. Organizations should enforce automated update policies across all endpoints running the affected browser versions to minimize exposure windows. Additionally, deploying content security policies and sandboxing mechanisms can limit the impact of successful exploits by restricting what resources web pages are allowed to interact with within the graphics subsystem. Regular vulnerability scanning and penetration testing focused on memory safety issues in third-party libraries used by browsers further strengthen defense-in-depth posture against such sophisticated attacks.