Overview
CVE-2025-9187 is a critical security vulnerability that affects users of Firefox and Thunderbird versions 141 and earlier. This flaw originates from memory safety bugs that have the potential to corrupt memory, allowing attackers to execute arbitrary codes. The severity of this vulnerability is underscored by its high CVSS score of 9.8, which signifies the potential for severe system compromise or data leakage. As Firefox and Thunderbird have millions of users worldwide, this vulnerability poses a significant risk, making its immediate mitigation a top priority.
Vulnerability Summary
CVE ID: CVE-2025-9187
Severity: Critical (CVSS: 9.8)
Attack Vector: Network
Privileges Required: None
User Interaction: Required
Impact: System compromise or data leakage
Affected Products
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Product | Affected Versions
Firefox | < 142 Thunderbird | < 142 How the Exploit Works
The vulnerability, CVE-2025-9187, stems from memory safety bugs present in Firefox and Thunderbird. The bugs could lead to memory corruption under certain conditions. An attacker could exploit these bugs to run arbitrary code on the victim’s system. This means the attacker could potentially gain control of the system, alter data, or leak sensitive information. The exploit would require user interaction, such as visiting a malicious website or opening a malicious email, making it a significant threat to all users of the affected software.
Conceptual Example Code
Below is a conceptual example of how the vulnerability might be exploited using a malicious JavaScript code on a webpage:
<html>
<body>
<script>
// Malicious code exploiting the memory safety bug
var largeArray = new Array(0xFFFFFFFF);
largeArray[0] = 'A';
// The result of this operation could potentially overflow memory and lead to code execution
largeArray.reverse();
</script>
</body>
</html>In this example, the JavaScript code creates an array with a length that is close to the maximum allowed value. It then tries to reverse the array, which could lead to memory overflow and potentially allow arbitrary code execution.
Users are strongly advised to update their Firefox and Thunderbird to the latest versions to mitigate this vulnerability. In the interim, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can help detect and prevent exploitation of this vulnerability.