CVE-2020-15673 in Firefox
Summary
by MITRE
Mozilla developers reported memory safety bugs present in Firefox 80 and Firefox ESR 78.2. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 81, Thunderbird < 78.3, and Firefox ESR < 78.3.
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Analysis
by VulDB Data Team • 05/05/2025
The vulnerability identified as CVE-2020-15673 represents a critical memory safety issue discovered within Mozilla Firefox and Thunderbird products. This flaw emerged in versions prior to Firefox 81 and Thunderbird 78.3, affecting both regular Firefox releases and the extended support release (ESR) versions. The vulnerability stems from memory safety bugs that were present in Firefox 80 and Firefox ESR 78.2, creating potential pathways for malicious exploitation. These memory safety issues are particularly concerning because they demonstrate evidence of memory corruption, which constitutes a fundamental weakness in software architecture that can lead to severe security implications. The presence of memory corruption vulnerabilities typically indicates that the application's memory management mechanisms have been compromised, potentially allowing attackers to manipulate program execution flow through crafted inputs or conditions.
The technical nature of this vulnerability aligns with common memory safety issues classified under CWE-122, which deals with buffer overflow conditions, and CWE-125, which addresses out-of-bounds read scenarios. These bugs occur when applications fail to properly validate memory access operations, leading to situations where attackers can overwrite memory locations or read unauthorized data. The memory corruption aspects suggest that the underlying software components responsible for handling user inputs, network data, or internal processing may have been exposed to improper memory access patterns. The vulnerability's potential for arbitrary code execution means that successful exploitation could allow attackers to gain complete control over affected systems, making it a high-priority concern for organizations relying on these applications. The flaw specifically impacts the memory management subsystems within Firefox's rendering engine and associated processing components, where improper handling of memory allocation and deallocation creates opportunities for malicious actors to manipulate program behavior.
From an operational impact perspective, this vulnerability affects a wide range of users who rely on Firefox and Thunderbird for their daily computing activities, including web browsing, email management, and document processing. Organizations that have not yet updated their systems to versions containing the necessary patches face significant risk exposure, as the vulnerability could be exploited through various attack vectors including malicious websites, email attachments, or crafted web content. The potential for remote code execution through memory corruption makes this particularly dangerous in enterprise environments where these applications are widely deployed. Security teams must consider the implications of this vulnerability across their entire network infrastructure, as compromised systems could serve as entry points for broader attacks. The vulnerability's impact extends beyond individual users to potentially affect organizational security postures, especially in environments where legacy systems or delayed patch management practices exist.
Mitigation strategies for CVE-2020-15673 should prioritize immediate patch deployment to ensure all affected systems are updated to versions containing the necessary memory safety fixes. Organizations should implement comprehensive patch management processes that include testing procedures to verify compatibility before deployment. Security monitoring should be enhanced to detect potential exploitation attempts through unusual memory access patterns or network traffic anomalies. The vulnerability highlights the importance of maintaining up-to-date software versions and implementing defense-in-depth strategies that include network segmentation, application whitelisting, and intrusion detection systems. Additionally, security awareness training should be reinforced to help users recognize potentially malicious content that might exploit these memory safety issues. Organizations should also consider implementing sandboxing mechanisms and privilege separation techniques to limit the potential impact of successful exploitation attempts. The remediation process should include verification procedures to confirm that systems are properly patched and that no residual vulnerabilities remain in the affected software components.