CVE-2023-23605 in Firefox
Summary
by MITRE • 06/02/2023
Mozilla developers and the Mozilla Fuzzing Team reported memory safety bugs present in Firefox 108 and Firefox ESR 102.6. 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 < 109, Firefox ESR < 102.7, and Thunderbird < 102.7.
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Analysis
by VulDB Data Team • 12/18/2025
This vulnerability represents a collection of memory safety issues discovered within the Mozilla Firefox browser and Thunderbird email client, specifically affecting versions prior to 109 for Firefox and 102.7 for Firefox ESR and Thunderbird. The identification of these flaws occurred through collaboration between Mozilla developers and their dedicated fuzzing team, highlighting the importance of automated security testing in identifying potential attack vectors. These memory safety bugs were particularly concerning because they demonstrated clear evidence of memory corruption, which is a critical class of vulnerabilities that can lead to system compromise. The presence of memory corruption indicators suggests that attackers could potentially exploit these weaknesses to execute arbitrary code on affected systems, making this a serious security concern for users of the affected software versions.
The technical nature of these vulnerabilities falls under the category of memory safety issues that are commonly tracked under CWE-787, which describes out-of-bounds write vulnerabilities, and CWE-788, which covers out-of-bounds read conditions. These flaws likely stem from insufficient bounds checking in memory management operations within the browser's rendering engine or JavaScript engine, where improper handling of memory allocation and deallocation can create exploitable conditions. The fuzzing process employed by Mozilla's security team is particularly effective at uncovering such issues because it systematically generates malformed inputs that can trigger unexpected behavior in software applications. When memory corruption occurs in browser environments, the consequences can be severe as modern browsers execute complex code from multiple sources and maintain extensive memory footprints that provide numerous potential attack surfaces.
The operational impact of this vulnerability extends beyond simple browser exploitation as it affects a widely used software ecosystem that serves as the primary interface for internet access for millions of users worldwide. Attackers who successfully exploit these memory corruption flaws could potentially gain complete control over affected systems, enabling them to execute malicious code, access sensitive data, or establish persistent backdoors. The vulnerability affects not only the standard Firefox browser but also Firefox Extended Support Release versions and Thunderbird email client, indicating a broad attack surface that could compromise user productivity and security across multiple applications. From an attacker's perspective, these memory safety issues present ideal targets for exploitation as they often allow for remote code execution without requiring user interaction, making them particularly dangerous in phishing campaigns or drive-by download scenarios.
The recommended mitigation strategy involves immediate upgrading to the patched versions of Firefox 109, Firefox ESR 102.7, and Thunderbird 102.7, which contain the necessary security fixes to address these memory safety issues. Organizations should prioritize deployment of these updates across their networks, particularly given the potential for remote exploitation and the demonstrated evidence of memory corruption. Security teams should also implement monitoring for any suspicious network activity that might indicate exploitation attempts, as these vulnerabilities could be actively targeted in the wild. Additionally, users should be educated about the importance of keeping their browser software updated and should avoid visiting untrusted websites or opening suspicious email attachments until the patches are applied. The vulnerability aligns with tactics documented in the ATT&CK framework under T1059, which covers command and control communications, and T1078, which addresses valid accounts, as exploitation could lead to persistent access to compromised systems. Regular security assessments should be conducted to ensure that all endpoints are properly patched and that the organization's security posture remains robust against similar memory safety vulnerabilities.