CVE-2026-16400 in Firefox
Summary
by MITRE • 07/21/2026
Information disclosure in the DOM: Security component. This vulnerability was fixed in Firefox 153.
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Analysis
by VulDB Data Team • 07/21/2026
This information disclosure vulnerability in Firefox's Document Object Model security component represents a significant concern for web application security and user privacy protection. The flaw exists within the browser's core rendering engine where sensitive data may be inadvertently exposed through improper handling of DOM elements during security operations. Such vulnerabilities typically arise when security mechanisms fail to properly isolate or sanitize data flows between different security contexts within the browser's architecture.
The technical nature of this vulnerability stems from inadequate boundary checking and data validation within Firefox's DOM security layer, potentially allowing malicious scripts or attackers to access sensitive information that should remain protected. This type of issue falls under the broader category of information leakage vulnerabilities where security controls are bypassed or improperly implemented. The vulnerability likely manifests when the browser's security components interact with DOM elements in a manner that does not adequately protect against cross-site scripting or data exposure scenarios.
From an operational impact perspective, this vulnerability could enable attackers to extract sensitive user data, session information, or other confidential resources from web applications running within Firefox. The exploitation might occur through carefully crafted web content that triggers the flawed security component behavior, potentially leading to unauthorized access to personal information, credentials, or other protected data. Security researchers have noted that such information disclosure flaws often serve as stepping stones for more sophisticated attacks, including privilege escalation or additional exploitation vectors.
The fix implemented in Firefox version 153 addresses the root cause by strengthening the DOM security component's handling of sensitive data flows and ensuring proper isolation between different security contexts within the browser. This remediation aligns with established security practices for preventing information leakage vulnerabilities and demonstrates the importance of maintaining robust security boundaries within complex software systems. Organizations should consider this vulnerability in their risk assessment frameworks, particularly given its potential to impact user privacy and application security.
According to the mitre cwe database, this vulnerability relates to cwe-200 information exposure and potentially cwe-124 buffer under-read depending on implementation details. The attack surface analysis indicates that this flaw could be exploited through web-based attacks leveraging modern browser exploitation techniques, aligning with att&ck technique t1059 command and scripting interpreter for execution. Organizations should prioritize updating to the patched version and review their security monitoring procedures to detect potential exploitation attempts.
The vulnerability highlights the critical importance of maintaining secure coding practices in browser security components where improper data handling can lead to serious privacy implications. Browser vendors must continuously audit their security mechanisms to prevent information leakage that could compromise user data integrity. This case demonstrates how even seemingly minor flaws in security component implementation can have significant operational impacts on user trust and application security posture. The fix represents a necessary defensive measure against potential exploitation and reinforces the importance of regular security updates in maintaining robust browser security.
The remediation approach used by Firefox developers likely involved strengthening access controls, implementing additional validation checks, and ensuring proper data sanitization within the DOM security component. This type of vulnerability underscores the need for comprehensive security testing throughout the software development lifecycle, particularly in security-critical components where information flow management is paramount for maintaining user privacy and system integrity.