CVE-2019-11740 in Firefox
Summary
by MITRE
Mozilla developers and community members reported memory safety bugs present in Firefox 68, Firefox ESR 68, and Firefox 60.8. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. This vulnerability affects Firefox < 69, Thunderbird < 68.1, Thunderbird < 60.9, Firefox ESR < 60.9, and Firefox ESR < 68.1.
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Analysis
by VulDB Data Team • 11/26/2025
This vulnerability represents a significant memory safety issue affecting multiple Mozilla products including Firefox and Thunderbird across several version lines. The reported memory safety bugs were identified by Mozilla's development team and community researchers, indicating a collaborative approach to security vulnerability detection. These particular flaws were classified as having evidence of memory corruption, which represents a critical class of vulnerabilities that can lead to system compromise. The presence of memory corruption vulnerabilities in widely used browser software creates substantial risk for end users who may be targeted through various attack vectors.
The technical nature of these memory safety bugs demonstrates a fundamental weakness in how the affected software handles memory allocation and deallocation processes. Memory corruption vulnerabilities typically arise from improper handling of buffer overflows, use-after-free conditions, or other memory management errors that can be exploited by malicious actors. The fact that these bugs were present in Firefox 68, Firefox ESR 68, and Firefox 60.8 indicates a widespread issue affecting both regular and extended support release versions. The vulnerability's potential for arbitrary code execution represents a severe operational impact, as successful exploitation could allow attackers to gain complete control over affected systems.
The affected product lines include Firefox versions prior to 69, Thunderbird versions prior to 68.1 and 60.9, and Firefox ESR versions prior to 60.9 and 68.1, demonstrating the broad scope of systems potentially at risk. This vulnerability aligns with common CWE categories such as CWE-121, which addresses stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow conditions. From an attacker's perspective, these memory corruption flaws represent attractive targets within the MITRE ATT&CK framework, particularly under the Tactic of Execution where adversaries attempt to run malicious code on compromised systems. The exploitation of such vulnerabilities typically follows patterns described in ATT&CK technique T1059, which covers command and scripting interpreter execution.
Organizations and individuals using affected versions should immediately implement mitigation strategies including updating to patched versions of the software. The vulnerability's classification as having evidence of memory corruption suggests that attackers with sufficient skill and resources could potentially develop working exploits. Security teams should prioritize patching these systems as they represent high-risk vulnerabilities that could be actively exploited in the wild. The presence of multiple affected versions across different product lines indicates that comprehensive vulnerability management efforts are required to ensure all potentially impacted systems receive appropriate updates and remediation measures.