CVE-2025-4918 is a critical vulnerability that allows an attacker to perform an out-of-bounds read or write on a JavaScript `Promise` object. This vulnerability affects several versions of Mozilla products, including Firefox versions earlier than 138.0.4, Firefox ESR versions earlier than 128.10.1 and 115.23.1, as well as Thunderbird versions earlier than 128.10.2 and 138.0.2. With a CVSS score of 9.8, this vulnerability poses a significant risk to users of these applications.
The critical nature of this vulnerability necessitates immediate action from organizations. The potential for an attacker to exploit this vulnerability could lead to unauthorized access, data corruption, and significant operational disruptions. Given its severe implications, organizations should prioritize patching immediately.
Currently, there are no known exploits available for this vulnerability, but the combination of its high severity and the potential impact necessitates a proactive approach to remediation. The urgency for defenders is heightened, and organizations must remain vigilant.
In summary, CVE-2025-4918 presents critical risks to Mozilla Firefox and Thunderbird users. The vulnerability's potential impact on confidentiality, integrity, and availability makes it imperative for organizations to address it without delay.
Vulnerability Details
CVE-2025-4918 allows attackers to exploit an out-of-bounds read or write on JavaScript `Promise` objects. This vulnerability is classified under CWE-125 (Out-of-bounds Read) and CWE-787 (Out-of-bounds Write). The affected products include Firefox and Thunderbird, with specific versions outlined above.
The CVSS version 3.1 score of 9.8 indicates that this vulnerability has a high impact on confidentiality, integrity, and availability, categorized as HIGH. It has a low attack complexity and does not require any privileges or user interaction, making it particularly dangerous.
Technical Analysis
The root cause of CVE-2025-4918 lies in improper handling of JavaScript `Promise` objects, which allows for out-of-bounds operations. Attackers can exploit this vulnerability over a network, leveraging the low complexity of the attack.
Since no privileges are required and user interaction is not necessary, the attack vector is significantly simplified. This can lead to substantial confidentiality, integrity, and availability impacts, as malicious actors may gain unauthorized access to sensitive information or disrupt system functionality.
Risk & Impact Analysis
Risk to organizations includes potential data breaches, unauthorized access to sensitive information, and operational disruptions. The blast radius of this vulnerability is extensive, affecting numerous users running outdated versions of Firefox and Thunderbird. The critical severity of this vulnerability, combined with the absence of any known exploits, emphasizes the necessity for organizations to remain proactive in their patching efforts.
As organizations evaluate their patch management practices, it is crucial to prioritize vulnerabilities like CVE-2025-4918 to mitigate the risk of exploitation. With a CVSS score of 9.8, this vulnerability should be at the forefront of any security strategy.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
This vulnerability affects Firefox versions below 138.0.4, Firefox ESR versions below 128.10.1 and 115.23.1, as well as Thunderbird versions below 128.10.2 and 138.0.2. Organizations should ensure that they update to the latest versions to mitigate the risks associated with this vulnerability.
Mitigation & Remediation
Organizations should prioritize patching by upgrading to Firefox 138.0.4, Thunderbird 128.10.2, or their respective ESR versions. If immediate patching is not feasible, organizations should implement network controls to limit the exposure of affected systems and consider configuration hardening as a temporary measure.
For further guidance on effective security practices, consider reviewing our penetration testing services.
Detection Guidance
Monitoring for unusual behavior in affected applications is crucial. Organizations should look for log indicators related to JavaScript execution errors, and any abnormal access patterns that deviate from normal usage. Additionally, keeping an eye on system changes can help detect potential exploitation attempts.
AppSecure Threat Intelligence Insight
CVE-2025-4918 highlights the ongoing challenges of software vulnerabilities in widely used applications like Mozilla Firefox and Thunderbird. The trend of out-of-bounds vulnerabilities signifies a need for enhanced security measures during the development process to thwart exploitation.
Security teams should take this incident as a lesson to reinforce their patch management strategies and ensure timely updates to reduce the attack surface. For insights into improving application security practices, consider exploring our vulnerability management program and our penetration testing methodology articles for best practices.
In conclusion, organizations must remain vigilant and proactive in addressing vulnerabilities like CVE-2025-4918 to safeguard their systems and data integrity.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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