CVE-2017-5398 in Firefox
Summary
by MITRE
Memory safety bugs were reported in Thunderbird 45.7. 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 < 52, Firefox ESR < 45.8, Thunderbird < 52, and Thunderbird < 45.8.
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Analysis
by VulDB Data Team • 11/26/2025
The vulnerability identified as CVE-2017-5398 represents a critical memory safety issue affecting Mozilla Thunderbird and Firefox browsers across multiple versions. This vulnerability stems from memory safety bugs that were discovered in Thunderbird 45.7, with the potential for exploitation through memory corruption techniques. The reported bugs demonstrate clear evidence of memory corruption vulnerabilities that could be leveraged by attackers to execute arbitrary code on affected systems. The scope of this vulnerability extends beyond Thunderbird to include Firefox browser versions prior to 52 and Firefox ESR versions prior to 45.8, making it a widespread concern for organizations using these web browsers. The vulnerability affects both desktop and mobile browser implementations, highlighting the critical nature of memory safety in browser applications where user interaction with potentially malicious content is common. These memory safety issues typically arise from improper handling of memory allocation, deallocation, or access patterns that can be exploited through crafted inputs or malicious web content.
The technical flaw underlying CVE-2017-5398 manifests as memory safety vulnerabilities that can lead to heap corruption, stack overflow, or use-after-free conditions within the browser's rendering engine or JavaScript engine. These memory corruption issues occur when the browser processes certain web content or handles specific data structures without proper bounds checking or memory validation. The vulnerability is particularly concerning because it affects the core components of web browsers that handle untrusted content from the internet, making them prime targets for exploitation. Attackers could potentially craft malicious web pages or email content that triggers these memory corruption issues when processed by vulnerable browser versions. The flaw typically involves improper memory management during object allocation, string handling, or DOM manipulation operations, which can be exploited through techniques such as buffer overflows, heap spraying, or return-oriented programming. This vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write conditions, both of which are common memory safety issues in browser environments.
The operational impact of CVE-2017-5398 is significant for organizations that rely on affected browser versions, as successful exploitation could result in complete system compromise. Attackers could leverage this vulnerability to execute arbitrary code with the privileges of the browser process, potentially leading to full system control, data exfiltration, or persistence mechanisms. The vulnerability affects both desktop and mobile users, making it particularly dangerous in enterprise environments where users may encounter malicious content through email, web browsing, or web applications. Organizations using Thunderbird for email processing face additional risk as the vulnerability affects email clients that handle untrusted content from external sources. The exploitation of this vulnerability could lead to privilege escalation, lateral movement within networks, and persistent backdoors. The memory corruption nature of the flaw makes exploitation particularly challenging for defenders, as it may not always be immediately apparent when a system has been compromised. This vulnerability also impacts the security posture of web applications that rely on these browsers for functionality, as attackers could use the compromised browser to target other systems or applications.
Mitigation strategies for CVE-2017-5398 should focus on immediate patching of affected software versions to eliminate the memory safety vulnerabilities. Organizations must prioritize updating to Firefox 52 or later, Firefox ESR 45.8 or later, Thunderbird 52 or later, and Thunderbird 45.8 or later to address the reported memory corruption issues. Security teams should implement network-based controls such as web application firewalls, content filtering systems, and email security solutions to detect and block malicious content that could exploit these vulnerabilities. Browser hardening techniques including disabling unnecessary browser features, implementing strict content security policies, and using sandboxing mechanisms can help reduce the attack surface. Additionally, organizations should deploy endpoint protection solutions that monitor for suspicious memory access patterns or process behavior that might indicate exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify systems running vulnerable software versions. The remediation process should include comprehensive testing of patched versions to ensure that security updates do not introduce compatibility issues with existing applications or services. Security awareness training for users should emphasize the importance of avoiding suspicious email attachments and web content that could trigger memory corruption vulnerabilities. The implementation of multi-factor authentication and network segmentation can provide additional layers of protection against successful exploitation attempts. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates across all affected systems.