CVE-2026-4693 in Firefox
Summary
by MITRE • 03/24/2026
Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
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Analysis
by VulDB Data Team • 04/16/2026
This vulnerability resides in the audio/video playback component of Mozilla Firefox and Thunderbird applications, representing a critical boundary condition flaw that could enable remote code execution under specific circumstances. The issue affects multiple product versions including Firefox versions prior to 149, Firefox ESR versions prior to 115.34 and 140.9, and Thunderbird versions prior to 149 and 140.9. The vulnerability stems from improper handling of boundary conditions within the multimedia playback engine, which processes various audio and video formats including but not limited to mp4, webm, and ogg containers. This flaw falls under the CWE-129 weakness category, which specifically addresses insufficient boundary checking in software implementations. The vulnerability represents a classic buffer overflow condition where the application fails to properly validate input boundaries when processing multimedia content, creating opportunities for attackers to manipulate memory layouts through crafted media files.
The operational impact of this vulnerability extends beyond simple playback failures, as it could potentially allow attackers to execute arbitrary code on affected systems. When a user opens a maliciously crafted media file or visits a website containing such content, the flawed boundary checking could lead to memory corruption that attackers might exploit to gain control over the affected application. This represents a significant risk in environments where users frequently access untrusted web content or receive email attachments containing multimedia content. The vulnerability's exploitation potential aligns with ATT&CK technique T1203, which covers exploitation of remote services, and T1059, covering command and scripting interpreter usage, as successful exploitation could provide attackers with persistent access to target systems. The attack surface includes web browsers, email clients, and any application that utilizes the affected multimedia playback libraries, making it particularly dangerous in enterprise environments where these applications are widely deployed.
Mitigation strategies should prioritize immediate patching of affected software versions, as Mozilla has released security updates addressing this vulnerability. Organizations should implement comprehensive software update management processes to ensure all affected systems receive patches promptly. Additional defensive measures include implementing content filtering solutions that can identify and block malicious media files, enabling sandboxing technologies that limit the potential impact of successful exploitation, and deploying network-based intrusion detection systems that can detect attempts to deliver malicious multimedia content. Security teams should also consider implementing user education programs to raise awareness about the risks of opening untrusted email attachments or visiting suspicious websites. The vulnerability demonstrates the importance of robust input validation and boundary checking in multimedia processing libraries, which should be reinforced through secure coding practices and regular security testing. Organizations should also conduct vulnerability assessments to identify any systems running unsupported versions of these applications, as the risk of exploitation increases significantly when systems are not running patched software versions.