CVE-2022-38478 in Thunderbird
Summary
by MITRE • 12/22/2022
Members the Mozilla Fuzzing Team reported memory safety bugs present in Firefox 103, Firefox ESR 102.1, and Firefox ESR 91.12. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Thunderbird < 102.2, Thunderbird < 91.13, Firefox ESR < 91.13, Firefox ESR < 102.2, and Firefox < 104.
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Analysis
by VulDB Data Team • 06/22/2026
This vulnerability represents a critical memory safety issue discovered within the Mozilla Firefox browser and Thunderbird email client ecosystems. The Mozilla Fuzzing Team identified multiple memory safety bugs that were present in several versions of these applications including Firefox 103, Firefox ESR 102.1, and Firefox ESR 91.12. These memory safety flaws constitute a significant security risk as they demonstrate evidence of memory corruption that could potentially be exploited by malicious actors to execute arbitrary code on affected systems. The vulnerability affects not only the main Firefox browser but also its extended support release versions and the Thunderbird email client across multiple version lines.
The technical nature of this vulnerability falls under memory safety issues that are commonly classified as CWE-122 (Heap-based Buffer Overflow) or similar memory corruption vulnerabilities. These types of flaws typically occur when applications fail to properly manage memory allocation and deallocation, leading to situations where attackers can manipulate memory contents to redirect program execution flow. The presence of memory corruption evidence suggests that attackers could potentially leverage these vulnerabilities to overwrite critical memory locations, manipulate program execution, or inject malicious code into the target system. The vulnerability's impact extends across multiple product lines including Thunderbird versions less than 102.2 and 91.13, Firefox ESR versions less than 91.13 and 102.2, and Firefox versions less than 104.
From an operational perspective, this vulnerability poses substantial risk to organizations and individual users who have not yet updated their software to patched versions. The potential for arbitrary code execution means that attackers could gain complete control over affected systems, potentially leading to data breaches, system compromise, or use as a foothold for further attacks within network environments. The vulnerability's presence in both current and extended support releases indicates that organizations using older versions of these applications face ongoing risk. The fact that these bugs were discovered through fuzzing operations suggests that they may be difficult to detect through conventional testing methods, making them particularly dangerous as they could remain undetected for extended periods.
The recommended mitigation strategy involves immediate application of available security patches and updates to all affected versions of Firefox, Thunderbird, and their respective extended support releases. Organizations should prioritize updating to versions that contain fixes for these memory safety issues, specifically targeting Firefox 104, Thunderbird 102.2, and the corresponding ESR versions. System administrators should implement comprehensive patch management procedures to ensure all endpoints are updated promptly. Additionally, organizations may consider implementing network monitoring and intrusion detection systems to identify potential exploitation attempts. The vulnerability's classification under memory safety flaws aligns with ATT&CK technique T1059.007 (Command and Scripting Interpreter: PowerShell) and T1078.004 (Valid Accounts: Cloud Accounts) when exploited, as attackers may leverage compromised systems for further malicious activities. Regular security assessments and vulnerability scanning should be conducted to identify any remaining unpatched systems within the organization's infrastructure.