CVE-2026-4712 in Firefox
Summary
by MITRE • 03/24/2026
Information disclosure in the Widget: Cocoa component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
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Analysis
by VulDB Data Team • 03/28/2026
The vulnerability identified as CVE-2026-4712 represents an information disclosure flaw within the Widget Cocoa component of Mozilla's Firefox and Thunderbird applications. This issue specifically impacts versions prior to Firefox 149 and Firefox ESR 140.9, as well as Thunderbird versions before 149 and Thunderbird ESR 140.9, indicating a widespread concern affecting multiple product lines within the Mozilla ecosystem. The Widget Cocoa component serves as a critical interface layer responsible for rendering graphical user interface elements on macOS platforms, making this vulnerability particularly concerning for users operating on Apple's operating system.
The technical nature of this information disclosure vulnerability stems from improper handling of sensitive data within the Cocoa component implementation. This flaw likely involves inadequate access controls or memory management practices that allow unauthorized retrieval of confidential information from the application's memory space or internal data structures. The vulnerability could potentially expose system information, user credentials, or other sensitive data that should remain protected within the application's secure execution environment. Such issues typically arise from insufficient input validation or improper boundary checking within the component's codebase, creating potential attack vectors for malicious actors to exploit.
From an operational perspective, this vulnerability poses significant risks to user privacy and system security across affected platforms. Attackers could potentially leverage this information disclosure to gather sensitive data that might aid in subsequent attacks, including credential harvesting, system reconnaissance, or privilege escalation attempts. The impact extends beyond individual user privacy concerns to potential corporate security implications, especially in environments where these applications are used for business-critical operations. The vulnerability's presence in both regular Firefox releases and ESR versions indicates that organizations relying on long-term support releases are equally at risk, potentially leaving extended deployment windows vulnerable to exploitation.
Security mitigations for this vulnerability primarily involve immediate application of available patches and updates from Mozilla's official release channels. Users should prioritize upgrading to Firefox 149 or later versions, Firefox ESR 140.9 or later, Thunderbird 149 or later, and Thunderbird ESR 140.9 or later to eliminate the risk associated with this information disclosure vulnerability. System administrators should implement comprehensive patch management procedures to ensure all affected systems receive updates promptly. Additionally, organizations should conduct vulnerability assessments to identify any systems still running vulnerable versions and implement network monitoring to detect potential exploitation attempts. This vulnerability aligns with CWE-200, which addresses information exposure, and may map to ATT&CK techniques involving reconnaissance and credential access through information gathering activities.
The broader implications of this vulnerability highlight the critical importance of maintaining up-to-date software security practices within enterprise environments. Organizations should establish robust security hygiene protocols that include regular vulnerability scanning, automated patch deployment, and continuous monitoring of security advisories from vendors like Mozilla. The presence of such information disclosure vulnerabilities in widely-used applications underscores the need for comprehensive security testing throughout the software development lifecycle, particularly for components that interface with operating system features like the Cocoa framework on macOS platforms. This incident serves as a reminder that even seemingly minor components within complex applications can present significant security risks when not properly secured against information disclosure threats.