CVE-2017-5470 in Firefox
Summary
by MITRE
Memory safety bugs were reported in Firefox 53 and Firefox ESR 52.1. 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 < 54, Firefox ESR < 52.2, and Thunderbird < 52.2.
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Analysis
by VulDB Data Team • 11/26/2025
The vulnerability identified as CVE-2017-5470 represents a critical memory safety issue within Mozilla Firefox and Thunderbird applications that emerged from the Firefox 53 and Firefox ESR 52.1 release cycles. This vulnerability classification falls under the CWE-119 category of "Improper Access to Memory" which encompasses various memory corruption flaws that can lead to arbitrary code execution. The reported memory safety bugs demonstrate evidence of memory corruption, indicating that attackers could potentially exploit these weaknesses to gain unauthorized control over affected systems. The vulnerability affects not only the standard Firefox browser but also the extended support release versions, creating a broad impact surface across multiple product lines and user bases. Security researchers identified these issues during routine code analysis and vulnerability assessment activities, highlighting the ongoing challenges in maintaining memory safety within complex browser applications that process untrusted web content.
The technical flaw manifests through memory safety bugs that allow for memory corruption, a condition where the application's memory management mechanisms fail to properly validate or control memory operations. These memory corruption vulnerabilities typically arise from improper handling of memory allocation, deallocation, or access patterns within the browser's rendering engine and JavaScript interpreter. When such flaws exist in browser applications, they create potential attack vectors where malicious actors can manipulate memory contents to execute arbitrary code. The vulnerability affects specific version ranges including Firefox versions prior to 54, Firefox ESR versions prior to 52.2, and Thunderbird versions prior to 52.2, indicating that these particular releases contained code paths that were susceptible to memory manipulation attacks. The presence of multiple affected products suggests that the underlying memory management issues were present across related software components and codebases.
The operational impact of CVE-2017-5470 extends significantly beyond simple browser functionality degradation, as memory corruption vulnerabilities can lead to complete system compromise when successfully exploited. Attackers leveraging these flaws could potentially execute malicious code with the privileges of the affected user, leading to data theft, system infiltration, or deployment of additional malware. The vulnerability's potential for arbitrary code execution aligns with ATT&CK technique T1059 which covers execution through command and scripting interpreters, as attackers could use the memory corruption to inject and run malicious code within the browser environment. Organizations running affected versions of Firefox or Thunderbird face substantial risk, as these browsers are commonly used for web browsing and email operations, making them attractive targets for cyber adversaries. The vulnerability's exploitation potential increases when considering that many users may not immediately update to patched versions, creating extended windows of exposure across enterprise and individual user environments.
Mitigation strategies for CVE-2017-5470 focus primarily on immediate version upgrades to patched releases, which represents the most effective remediation approach. Organizations should prioritize updating Firefox to version 54 or later, Firefox ESR to version 52.2 or later, and Thunderbird to version 52.2 or later to eliminate the memory safety vulnerabilities. System administrators should implement automated patch management processes to ensure timely deployment of security updates across all affected systems. Additional defensive measures include implementing browser hardening techniques such as enabling sandboxing features, restricting browser privileges, and employing network monitoring to detect anomalous behavior that might indicate exploitation attempts. Security teams should also consider deploying web application firewalls and content filtering solutions to reduce exposure to potentially malicious web content. The vulnerability underscores the importance of maintaining up-to-date software deployments and implementing comprehensive security practices that include regular vulnerability assessments, penetration testing, and security awareness training for end users to prevent exploitation through social engineering or other attack vectors.