CVE-2022-22751 in Thunderbird
Summary
by MITRE • 12/22/2022
Mozilla developers Calixte Denizet, Kershaw Chang, Christian Holler, Jason Kratzer, Gabriele Svelto, Tyson Smith, Simon Giesecke, and Steve Fink reported memory safety bugs present in Firefox 95 and Firefox ESR 91.4. 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 < 91.5, Firefox < 96, and Thunderbird < 91.5.
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Analysis
by VulDB Data Team • 04/28/2026
This vulnerability represents a collection of memory safety issues discovered in Mozilla Firefox and Thunderbird products, specifically affecting versions prior to Firefox ESR 91.5, Firefox 96, and Thunderbird 91.5. The reporting team consisted of multiple experienced developers from Mozilla including Calixte Denizet, Kershaw Chang, Christian Holler, Jason Kratzer, Gabriele Svelto, Tyson Smith, Simon Giesecke, and Steve Fink who identified these critical flaws in the browser's memory management systems. These memory safety bugs were particularly concerning because they demonstrated clear evidence of memory corruption capabilities that could potentially be exploited by malicious actors.
The technical nature of these vulnerabilities stems from fundamental issues within Firefox's memory handling mechanisms, which are classified under common weakness enumeration CWE-787 and CWE-788 representing out-of-bounds writes and reads. When applications fail to properly validate memory access operations, they create opportunities for attackers to manipulate memory contents in ways that can lead to arbitrary code execution. The bugs were found to be present in both the main Firefox browser and its extended support release versions, as well as in Thunderbird email client software, indicating a widespread impact across Mozilla's product ecosystem.
The operational impact of these vulnerabilities is severe given that they could potentially allow remote attackers to execute arbitrary code on affected systems. Memory corruption flaws represent one of the most dangerous categories of security issues because they can be leveraged to bypass modern security protections like address space layout randomization and data execution prevention. Attackers could exploit these weaknesses by crafting malicious web content or email messages that trigger the vulnerable memory operations, potentially leading to complete system compromise. The fact that these bugs were present in both regular Firefox releases and ESR versions means that organizations relying on extended support channels were also at risk.
Mitigation strategies for this vulnerability include immediate deployment of security updates to Firefox ESR 91.5, Firefox 96, and Thunderbird 91.5 releases which contain patches addressing the identified memory safety issues. Organizations should prioritize updating their systems as these vulnerabilities have a high potential for exploitation given their nature as memory corruption flaws. Additionally, users should be advised against visiting untrusted websites or opening suspicious email attachments until updates are applied. Security teams should monitor for any reported exploitation attempts and consider implementing network-based protections such as web application firewalls to detect and block malicious content that might attempt to exploit these vulnerabilities during the transition period before full patch deployment occurs. The ATT&CK framework categorizes these issues under T1059 (Command and Scripting Interpreter) and T1203 (Exploitation for Client Execution) due to their potential for arbitrary code execution through memory corruption techniques.