CVE-2022-38477 in Thunderbird
Summary
by MITRE • 12/22/2022
Mozilla developer Nika Layzell and the Mozilla Fuzzing Team reported memory safety bugs present in Firefox 103 and Firefox ESR 102.1. 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 Firefox ESR < 102.2, Thunderbird < 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 in Mozilla Firefox and Thunderbird products, specifically affecting versions prior to 102.2 for ESR releases and 104 for standard Firefox releases. The flaw was identified through systematic fuzzing efforts by Mozilla's security team and external researchers, highlighting the ongoing challenges in maintaining memory safety within complex browser environments. These memory safety bugs fall under the broader category of memory corruption vulnerabilities that have historically been exploited to achieve arbitrary code execution. The reported issues demonstrate the persistent risk that memory safety flaws pose to web browser security, particularly given the privileged execution context that browsers operate in when processing web content.
The technical nature of this vulnerability stems from memory safety issues that can manifest as buffer overflows, use-after-free conditions, or other memory corruption patterns commonly found in C/C++ based applications. These types of flaws typically occur when applications fail to properly validate memory access operations or when they improperly handle memory allocation and deallocation processes. The presence of evidence suggesting potential exploitation pathways indicates that attackers could leverage these memory corruption vulnerabilities to execute malicious code remotely, potentially compromising user systems. Such vulnerabilities are particularly dangerous in browser contexts where users frequently interact with untrusted web content, creating numerous attack vectors for exploitation.
The operational impact of this vulnerability extends beyond simple memory corruption to encompass potential full system compromise when successfully exploited. Attackers could potentially leverage these flaws to bypass security mitigations such as address space layout randomization and data execution prevention. The vulnerability affects both Firefox and Thunderbird products, indicating a widespread impact across Mozilla's suite of applications, which increases the potential attack surface. Security researchers have noted that these memory safety issues could enable sophisticated attack techniques such as heap spraying or return-oriented programming to achieve code execution. The vulnerability's classification aligns with CWE-122 (Heap-based Buffer Overflow) and CWE-476 (NULL Pointer Dereference) categories, which represent common memory safety flaws in software applications.
Organizations must prioritize immediate patching of affected systems to mitigate this vulnerability, as the potential for exploitation remains high given the nature of memory corruption flaws. The recommended mitigation strategy involves updating to Firefox ESR 102.2 or later versions, Thunderbird 102.2 or later, and Firefox 104 or later releases. Security teams should implement network monitoring to detect potential exploitation attempts and consider deploying additional security controls such as exploit prevention software and application whitelisting. The vulnerability demonstrates the importance of continuous security testing and the value of fuzzing programs in identifying memory safety issues before they can be exploited in the wild. Organizations should also review their incident response procedures to ensure readiness for potential exploitation attempts, as these types of vulnerabilities often become targets for advanced persistent threats and zero-day exploits.