CVE-2026-16410 in Firefox
Summary
by MITRE • 07/21/2026
JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 153.
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Analysis
by VulDB Data Team • 07/21/2026
This vulnerability represents a critical just-in-time compilation flaw within the JavaScript engine's optimization layer that could potentially allow attackers to execute arbitrary code through malformed JavaScript input. The issue specifically affects the JIT compiler component responsible for translating JavaScript code into optimized machine instructions during runtime. When processing certain JavaScript constructs, the compiler fails to properly validate or handle specific code patterns, leading to incorrect instruction generation that can be exploited by malicious actors.
The technical nature of this vulnerability stems from improper handling of code optimization decisions within the JIT compilation pipeline. This miscompilation occurs when the engine's optimizer makes incorrect assumptions about code behavior or memory layout, resulting in corrupted execution paths that can be manipulated by attackers. The flaw typically manifests when the JIT compiler encounters complex JavaScript code structures that trigger faulty optimization logic, causing it to generate machine code that behaves differently than intended during execution.
The operational impact of this vulnerability extends beyond simple browser exploitation as it represents a potential pathway for remote code execution attacks. Attackers could craft malicious JavaScript payloads designed to trigger the specific JIT miscompilation scenario, potentially leading to full system compromise when executed in vulnerable Firefox versions. This type of vulnerability is particularly dangerous because it operates at the core optimization layer where performance enhancements meet security considerations, making detection and exploitation more sophisticated than traditional buffer overflow or injection attacks.
Security researchers have classified this issue as a memory safety vulnerability that could enable privilege escalation or arbitrary code execution under specific conditions. The fix implemented in Firefox 153 addresses the root cause by strengthening the JIT compiler's validation mechanisms and ensuring proper handling of edge cases during optimization processes. Organizations should prioritize updating to this patched version and monitor for any related exploitation attempts targeting similar JIT vulnerabilities in other browser engines.
This vulnerability aligns with common attack patterns documented in the attack technique framework, particularly those involving compiler-based attacks and optimization flaws that bypass traditional security controls. The remediation strategy focuses on strengthening the JIT compiler's integrity checks and implementing additional validation layers to prevent incorrect code generation. Security professionals should consider this as part of broader browser hardening efforts and monitor for similar issues in other JavaScript engines where comparable JIT optimization components exist, as these vulnerabilities often share common underlying architectural weaknesses that can be exploited across different implementations.