CVE-2018-5089 in Firefox
Summary
by MITRE
Memory safety bugs were reported in Firefox 57 and Firefox ESR 52.5. 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 < 52.6, Firefox ESR < 52.6, and Firefox < 58.
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Analysis
by VulDB Data Team • 11/26/2025
CVE-2018-5089 represents a collection of memory safety vulnerabilities discovered in Mozilla Firefox and Thunderbird products, specifically impacting versions prior to 52.6 for ESR releases and 58 for standard releases. These vulnerabilities stem from fundamental flaws in how the applications handle memory allocation and deallocation processes, creating potential entry points for malicious actors to execute arbitrary code on affected systems. The reported memory safety bugs demonstrate evidence of memory corruption, which occurs when programs write data beyond allocated memory boundaries or access freed memory regions. Such corruption can lead to unpredictable program behavior, crashes, or more critically, provide attackers with opportunities to inject and execute malicious code within the application's memory space.
The technical nature of these vulnerabilities aligns with common CWE categories including CWE-121, heap-based buffer overflow, and CWE-125, out-of-bounds read conditions, which are typical manifestations of memory safety issues in complex software applications. These flaws often arise from inadequate bounds checking during memory operations, particularly in JavaScript engines and rendering components where memory management becomes particularly complex. The vulnerability's impact is significant because it affects not only the browser's core functionality but also extends to the email client Thunderbird, indicating widespread exposure across Mozilla's product ecosystem. Attackers exploiting these memory corruption issues could potentially leverage techniques such as return-oriented programming or use-after-free attacks to gain control over the affected applications' execution flow.
The operational impact of CVE-2018-5089 extends beyond simple application instability, as successful exploitation could enable attackers to execute arbitrary code with the privileges of the affected user. This presents a serious threat to enterprise environments where these applications are widely deployed, as compromised systems could serve as entry points for broader network infiltration. The vulnerability's presence in both regular Firefox releases and Extended Support Releases (ESR) indicates that organizations maintaining older versions for stability reasons remain at risk, as ESR versions typically receive extended support periods but still contain these memory safety flaws. Security teams must consider the implications of these vulnerabilities when assessing risk exposure, particularly in environments where users have elevated privileges or access to sensitive data.
Organizations should prioritize immediate patching of affected systems, as Mozilla released updates addressing these memory safety issues in versions 52.6 and 58 respectively. The remediation process should include comprehensive testing to ensure that updates do not introduce compatibility issues with existing applications or workflows. Additional mitigations may include implementing application whitelisting, restricting user privileges, and deploying intrusion detection systems to monitor for suspicious activities that might indicate exploitation attempts. Security professionals should also consider the broader context of these vulnerabilities within the ATT&CK framework, particularly focusing on techniques related to code injection and privilege escalation that could result from successful exploitation of memory corruption flaws. Regular vulnerability assessments and security audits should be conducted to identify similar memory safety issues in other applications within the organization's attack surface, as these types of vulnerabilities often indicate underlying architectural weaknesses that may be present elsewhere in the software stack.