CVE-2022-22740 in Thunderbird
Summary
by MITRE • 12/22/2022
Certain network request objects were freed too early when releasing a network request handle. This could have lead to a use-after-free causing a potentially exploitable crash. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.
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Analysis
by VulDB Data Team • 04/17/2025
This vulnerability represents a classic use-after-free condition that occurs during the cleanup process of network request handling within Mozilla's browser and email client applications. The flaw manifests when network request objects are prematurely deallocated while still being referenced or accessed by the application's networking subsystem. This timing issue creates a scenario where subsequent operations attempting to access the freed memory location could result in unpredictable behavior including application crashes or potential code execution. The vulnerability specifically impacts the memory management routines responsible for releasing network request handles, where the destruction sequence does not properly account for all active references to the underlying objects.
The technical implementation of this vulnerability stems from improper object lifecycle management within the networking component of Firefox and Thunderbird. When a network request handle is released, the system attempts to free associated memory resources before ensuring all references to those resources have been properly dereferenced. This creates a window where malicious actors could potentially exploit the dangling pointer by manipulating the application's state to force access to the freed memory location. The flaw aligns with CWE-416, which specifically addresses use-after-free vulnerabilities where memory is accessed after it has been freed, and represents a critical memory safety issue that could be leveraged for remote code execution in certain circumstances.
The operational impact of this vulnerability extends across multiple affected versions of Mozilla's flagship products, with Firefox ESR versions prior to 91.5 and standard Firefox versions before 96 being particularly susceptible. Thunderbird versions below 91.5 also remain at risk, highlighting the widespread nature of this memory management flaw. Attackers could potentially exploit this vulnerability through malicious web content or email messages that trigger specific network request patterns, leading to arbitrary code execution on vulnerable systems. The exploitability of this condition depends on the attacker's ability to control the timing and nature of network requests to create the precise conditions required to trigger the use-after-free scenario.
Mitigation strategies for this vulnerability focus on immediate patch deployment across all affected software versions, with security updates addressing the underlying memory management issues in the networking subsystem. Organizations should prioritize updating to the latest stable releases of Firefox ESR 91.5, Firefox 96, and Thunderbird 91.5 to eliminate the risk of exploitation. Additionally, network administrators should consider implementing additional security controls such as web application firewalls and content filtering systems to reduce the attack surface for potential exploitation attempts. The vulnerability demonstrates the critical importance of proper memory management practices in complex software systems and aligns with ATT&CK technique T1059.007 for command and scripting interpreter, where exploitation could potentially lead to persistent access through remote code execution. System administrators should also monitor for any suspicious network activity or application crashes that might indicate attempted exploitation of this vulnerability.