CVE-2026-4694 in Firefox
Summary
by MITRE • 03/24/2026
Incorrect boundary conditions, integer overflow in the Graphics 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 represents a critical integer overflow condition within the graphics component of Mozilla Firefox and Thunderbird applications. The flaw manifests as incorrect boundary conditions that can lead to memory corruption when processing specially crafted graphical content. The vulnerability 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, indicating a widespread impact across the Mozilla ecosystem. The technical nature of this vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions, and represents a classic example of how boundary checks can fail in graphics processing pipelines. The vulnerability occurs when the graphics component fails to properly validate input parameters during rendering operations, potentially allowing an attacker to manipulate memory layout through crafted graphical elements.
The operational impact of this vulnerability extends beyond simple memory corruption, as it can potentially enable arbitrary code execution under specific conditions. Attackers can exploit this flaw by delivering malicious content that triggers the vulnerable graphics processing path, typically through web pages containing crafted images or vector graphics. The integer overflow can lead to buffer overflows, memory corruption, or other exploitable conditions that may allow attackers to execute malicious code with the privileges of the affected application. This vulnerability particularly affects web browsers since they must process diverse graphical content from untrusted sources, making the attack surface significant. The ATT&CK framework categorizes this as a memory corruption vulnerability that could be leveraged for privilege escalation or code execution through techniques such as stack smashing or heap spraying.
Mitigation strategies for this vulnerability require immediate patching of affected software versions to address the underlying integer overflow conditions in the graphics processing components. Organizations should prioritize updating Firefox and Thunderbird installations to their latest versions, particularly focusing on the ESR releases that address this specific flaw. System administrators should implement network-based protections such as content filtering and sandboxing to reduce the risk of exploitation, while also monitoring for indicators of compromise related to exploitation attempts. The fix typically involves implementing proper boundary checking and input validation within the graphics processing pipeline, ensuring that all integer operations are properly constrained and validated before memory allocation occurs. Additionally, deploying web application firewalls and implementing strict content security policies can help prevent exploitation attempts through web-based attack vectors. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of the vulnerable software within the organization's infrastructure.