CVE-2013-5597 in Firefox
Summary
by MITRE
Use-after-free vulnerability in the nsDocLoader::doStopDocumentLoad function in Mozilla Firefox before 25.0, Firefox ESR 17.x before 17.0.10 and 24.x before 24.1, Thunderbird before 24.1, Thunderbird ESR 17.x before 17.0.10, and SeaMonkey before 2.22 allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) via vectors involving a state-change event during an update of the offline cache.
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Analysis
by VulDB Data Team • 11/25/2025
The CVE-2013-5597 vulnerability represents a critical use-after-free condition that existed in Mozilla's web browser and email client software ecosystems. This flaw was present in Firefox versions prior to 25.0, Firefox ESR 17.x versions before 17.0.10, and 24.x versions before 24.1, as well as in Thunderbird and SeaMonkey applications. The vulnerability specifically manifested within the nsDocLoader::doStopDocumentLoad function, which is responsible for managing document loading operations and cache updates. This particular code path handled state-change events during offline cache updates, creating a dangerous scenario where memory previously freed by the application could be accessed and manipulated by malicious actors.
The technical exploitation of this vulnerability occurs through a carefully crafted sequence involving document loading and cache management operations. When the browser encounters a state-change event during an offline cache update, the nsDocLoader::doStopDocumentLoad function fails to properly manage memory references, leading to a use-after-free condition. This memory corruption occurs in heap memory regions that have already been deallocated, allowing attackers to manipulate freed memory pointers and potentially execute arbitrary code. The vulnerability's nature aligns with CWE-416, which specifically addresses use-after-free conditions, and it demonstrates how improper memory management in complex web browser components can create exploitable scenarios. The attack vector requires remote code execution through web content, making it particularly dangerous as it can be triggered simply by visiting a malicious website or receiving specially crafted email content.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to encompass full remote code execution capabilities. Attackers could leverage this flaw to install malware, steal user data, or completely compromise affected systems without user interaction beyond visiting malicious web pages. The vulnerability's presence across multiple Mozilla products including Firefox, Thunderbird, and SeaMonkey meant that organizations using any of these applications were potentially at risk, with the severity amplified by the widespread adoption of these browsers and email clients. The heap memory corruption resulting from this use-after-free condition could lead to unpredictable behavior including application crashes, data corruption, or complete system compromise depending on the execution environment and attacker sophistication. This vulnerability directly relates to ATT&CK technique T1059, which involves executing malicious code through compromised applications, and demonstrates how vulnerabilities in core browser functionality can be weaponized for advanced persistent threats.
Mitigation strategies for CVE-2013-5597 required immediate application of vendor security patches and updates to affected software versions. Organizations needed to prioritize updating Firefox, Thunderbird, and SeaMonkey installations to versions that contained fixes for the memory management issue in nsDocLoader::doStopDocumentLoad. The recommended approach involved implementing a comprehensive patch management program to ensure all affected systems received updates promptly. Browser vendors had to implement proper memory deallocation and reference management within the affected code paths to prevent the use-after-free condition from occurring. Additionally, network security measures such as web application firewalls and content filtering systems could provide additional protection layers while awaiting full patch deployment. Security monitoring became crucial for detecting exploitation attempts, as the vulnerability could be used in targeted attacks against specific organizations or individuals, making continuous threat hunting and incident response protocols essential for organizations that could not immediately apply patches.