CVE-2018-5187 in Firefox
Summary
by MITRE
Memory safety bugs present in Firefox 60 and Firefox ESR 60. 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 Thunderbird < 60, Firefox ESR < 60.1, and Firefox < 61.
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Analysis
by VulDB Data Team • 11/26/2025
The vulnerability identified as CVE-2018-5187 represents a critical memory safety issue affecting Mozilla Firefox and Thunderbird products. This vulnerability encompasses multiple memory safety bugs that were discovered in Firefox version 60 and Firefox ESR 60, with the potential for exploitation leading to arbitrary code execution. The nature of these bugs indicates they could result in memory corruption, a condition that fundamentally compromises the integrity of the application's memory management systems.
These memory safety flaws fall under the broader category of memory corruption vulnerabilities that are particularly dangerous because they can be exploited by attackers to gain unauthorized control over affected systems. The vulnerability affects not only the standard Firefox browser but also Thunderbird email client, as well as older versions of Firefox ESR that have not received the necessary security patches. The specific versions impacted include Thunderbird versions prior to 60, Firefox ESR versions prior to 60.1, and Firefox versions prior to 61. This widespread impact across multiple Mozilla products demonstrates the severity of the underlying memory management issues.
The technical implications of these memory safety bugs are significant from a cybersecurity perspective, as they represent potential entry points for malicious actors seeking to compromise user systems. Memory corruption vulnerabilities are particularly concerning because they can lead to unpredictable behavior in applications, potentially allowing attackers to execute malicious code with the privileges of the affected application. The presence of evidence suggesting these bugs could result in memory corruption indicates that they may be exploitable through techniques such as buffer overflows or use-after-free conditions that are commonly targeted in exploit development.
From a threat modeling standpoint, these vulnerabilities align with attack patterns described in the MITRE ATT&CK framework under techniques related to privilege escalation and code execution. The potential for arbitrary code execution makes these vulnerabilities particularly attractive to threat actors who may attempt to leverage them for more sophisticated attacks. The fact that these bugs were present in widely used software applications increases their potential impact, as they could affect millions of users who rely on these browsers and email clients for daily operations.
Organizations and individuals should prioritize immediate patching of affected systems to mitigate the risk associated with these memory safety vulnerabilities. The recommended mitigation strategy involves updating to the latest versions of Firefox, Thunderbird, and Firefox ESR that contain the necessary security fixes. Security teams should also implement monitoring for any signs of exploitation attempts targeting these specific vulnerabilities. The vulnerability classification aligns with CWE entries related to memory safety issues, particularly those concerning buffer overflows and memory corruption that can lead to arbitrary code execution.
The broader implications of CVE-2018-5187 extend beyond individual system compromise to potentially affect organizational security postures. Given that these vulnerabilities affect software that is commonly used for business communications and web browsing, the potential for lateral movement within networks or data exfiltration increases significantly. Security professionals should consider these vulnerabilities as part of their comprehensive risk assessment and ensure that their incident response procedures include detection and remediation capabilities for memory corruption exploits. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date software and implementing robust patch management processes to protect against known security flaws.