CVE-2026-16368 in Firefox
Summary
by MITRE • 07/21/2026
Incorrect boundary conditions in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 153 and Firefox ESR 140.13.
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Analysis
by VulDB Data Team • 07/21/2026
This vulnerability represents a critical boundary condition flaw within the JavaScript WebAssembly component of Mozilla Firefox browsers. The issue stems from improper validation of memory boundaries when processing WebAssembly modules, creating potential pathways for arbitrary code execution through malformed or maliciously constructed web assembly binaries. Such vulnerabilities typically arise when developers fail to adequately check array indices, buffer limits, or memory access boundaries during WebAssembly module parsing and execution phases.
The technical nature of this flaw allows attackers to manipulate WebAssembly memory management routines by crafting specially designed WebAssembly modules that exceed normal boundary constraints. When Firefox processes these malformed modules, the insufficient boundary checking can lead to memory corruption issues that may be exploited to execute arbitrary code with the privileges of the browser process. This type of vulnerability falls under the broader category of buffer overflow conditions and memory safety violations commonly classified as CWE-129 or CWE-787 depending on the specific implementation details.
From an operational perspective, this vulnerability poses significant risks to web application security as it enables remote code execution through standard web browsing activities. The impact extends beyond simple browser compromise since WebAssembly is increasingly used in modern web applications for performance-critical operations including cryptography, multimedia processing, and data compression. Attackers could leverage this vulnerability to bypass security mechanisms, escalate privileges, or establish persistent access points within victim environments.
The fix implemented in Firefox 153 and Firefox ESR 140.13 addresses the core boundary condition validation issues by strengthening memory access checks during WebAssembly module processing. This remediation follows established security practices aligned with the principle of least privilege and defensive programming techniques that are recommended in various cybersecurity frameworks including those outlined in the ATT&CK framework under the execution and privilege escalation tactics. Organizations should prioritize immediate deployment of these patches to protect against potential exploitation attempts targeting this specific vulnerability.
Security teams should consider implementing additional monitoring for suspicious WebAssembly module loading activities and maintain awareness of related vulnerabilities in web assembly implementations across different browser vendors. The fix demonstrates the importance of comprehensive boundary condition validation in complex software components and reinforces the need for continuous security auditing of core browser functionalities that handle untrusted input data streams.