CVE-2026-100782 in Firefox
Summary
by MITRE • 09/29/2026
Privilege escalation due to incorrect boundary conditions in the Graphics component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
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Analysis
by VulDB Data Team • 09/29/2026
The identified security flaw resides within the graphics subsystem of Mozilla Firefox, specifically involving incorrect boundary conditions that facilitate privilege escalation. This type of vulnerability typically arises when the software fails to properly validate input data or memory boundaries during rendering operations, allowing an attacker to write beyond allocated limits or execute code in a context with higher privileges than intended. In modern web browsers, the graphics component is responsible for handling complex visual computations, including GPU acceleration and canvas rendering. When boundary checks are insufficient, maliciously crafted content can exploit these gaps to corrupt memory structures, potentially leading to arbitrary code execution within the browser process. This represents a significant security risk as it undermines the isolation mechanisms designed to contain web content in sandboxed environments.
From a technical perspective, this vulnerability aligns with common weaknesses such as CWE-120 Buffer Overflow or CWE-787 Out-of-bounds Write, depending on the specific implementation details of how memory is managed during graphics processing. The incorrect boundary conditions suggest that the application did not adequately verify indices or sizes before performing operations on arrays or buffers associated with graphical elements. An attacker could leverage this by hosting a webpage containing specially crafted JavaScript and HTML5 canvas code designed to trigger these faulty checks. By manipulating pixel data, texture coordinates, or shader inputs, it is possible to cause memory corruption that allows for the escalation of privileges from the low-privilege renderer process to higher-level processes or even system level access if further exploitation chains are present.
The operational impact of this vulnerability is severe due to its potential for remote code execution without user interaction beyond visiting a malicious site. If successfully exploited, an attacker could gain control over the browser session, leading to data theft, installation of malware, or use of the compromised machine as part of a botnet. This aligns with MITRE ATT&CK techniques related to initial access and privilege escalation, particularly those involving exploitation for client-side code execution. The ability to escalate privileges within the application context can also facilitate lateral movement if other services are accessible from the browser environment.
To mitigate this risk, users must ensure they are running patched versions of Firefox that include fixes for these boundary condition errors. Specifically, updating to Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, or Firefox ESR 140.17 is essential as these releases contain the necessary code corrections to enforce proper memory bounds checking in the graphics component. Organizations should prioritize patching their endpoints with these updates and consider implementing browser hardening policies such as disabling unnecessary plugins or restricting script execution on untrusted sites where possible. Regular security audits and monitoring for anomalous behavior can also help detect potential exploitation attempts before they result in a full compromise.