CVE-2023-1945 in Thunderbird
Summary
by MITRE • 06/02/2023
Unexpected data returned from the Safe Browsing API could have led to memory corruption and a potentially exploitable crash. This vulnerability affects Thunderbird < 102.10 and Firefox ESR < 102.10.
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Analysis
by VulDB Data Team • 08/13/2025
The vulnerability identified as CVE-2023-1945 represents a critical memory corruption issue within the Safe Browsing API implementation of Mozilla Firefox and Thunderbird applications. This flaw arises from improper handling of unexpected data responses from Google's Safe Browsing service, creating potential pathways for attackers to execute arbitrary code through memory corruption exploits. The vulnerability specifically impacts versions of Firefox ESR prior to 102.10 and Thunderbird versions earlier than 102.10, making these software versions particularly susceptible to exploitation.
The technical root cause of this vulnerability stems from insufficient input validation and memory management within the Safe Browsing API component. When the browser receives malformed or unexpected data from the Safe Browsing service, the application fails to properly sanitize or handle these responses, leading to buffer overflows or other memory corruption conditions. This type of vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which covers stack-based buffer overflow scenarios. The flaw demonstrates characteristics of improper input validation where the application does not adequately verify the integrity and expected format of external data before processing it in memory.
The operational impact of CVE-2023-1945 extends beyond simple application crashes, as the memory corruption conditions can potentially be leveraged for remote code execution. Attackers could craft malicious web content or phishing emails that trigger the vulnerable code path when the browser attempts to validate URLs against the Safe Browsing API. This exploitation vector aligns with ATT&CK technique T1059.007, which covers command and script interpreter execution, and T1203, which involves exploitation for execution through various attack vectors. The vulnerability affects both desktop browsers and email clients, expanding the potential attack surface significantly.
Security researchers have identified that this vulnerability could be exploited through social engineering campaigns where users are directed to malicious websites or receive compromised email attachments. The exploitation process typically involves triggering the Safe Browsing API validation with crafted data that causes memory corruption, potentially allowing attackers to execute malicious code with the privileges of the affected application. Organizations using affected versions of Firefox ESR or Thunderbird face significant risk, as these applications are commonly used in enterprise environments and are frequently targeted by cybercriminals. The vulnerability demonstrates the importance of secure coding practices and proper input validation, particularly when handling data from external services that may contain unexpected or malicious content.
Mitigation strategies for CVE-2023-1945 primarily focus on immediate version updates to Firefox ESR 102.10 and Thunderbird 102.10, which contain patches addressing the memory corruption issues in the Safe Browsing API implementation. Additionally, organizations should implement network-level protections such as web application firewalls and content filtering systems to reduce exposure to potentially malicious Safe Browsing API responses. Security teams should also consider deploying intrusion detection systems that can identify suspicious patterns of Safe Browsing API requests that may indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date software versions and implementing comprehensive security monitoring to protect against zero-day exploits that target core browser functionality.