CVE-2026-2739 is a medium-severity vulnerability affecting versions of the package bn.js prior to 5.2.3. This vulnerability allows an attacker to invoke the method maskn(0) on any BN instance, which corrupts the internal state of the application. As a result, methods such as toString() and divmod() can enter an infinite loop, causing the process to hang indefinitely. The CVSS score of 5.5 indicates that while the impact on availability is low, the potential for denial of service requires attention.
Given the exploitability of this vulnerability, organizations using affected versions of bn.js should prioritize remediation. Although the vulnerability is currently awaiting analysis, delaying action may lead to significant service disruptions if it becomes actively exploited.
Risk to organizations includes the potential for service outages, which may disrupt business operations. Organizations should assess their use of bn.js and implement necessary updates to mitigate this risk.
Urgency for defenders is moderate, as organizations should schedule remediation in their patch cycles. Regular updates and monitoring for vulnerabilities remain crucial to maintaining operational integrity.
Vulnerability Details
This vulnerability affects versions of the package bn.js before 5.2.3. The official description states that calling maskn(0) on any BN instance corrupts the internal state, causing toString(), divmod(), and other methods to enter an infinite loop, hanging the process indefinitely.
The CVSS score for this vulnerability is 5.5, categorized as medium severity. This assessment reflects the potential impact on availability, which is deemed low, while the attack vector is classified as network-based with low complexity and no privileges required.
The vulnerability is classified under CWE-835, indicating that it allows for denial of service conditions.
Technical Analysis
The root cause of CVE-2026-2739 lies in the improper handling of internal state within the bn.js library. When the maskn(0) method is called, it corrupts the internal state, leading to the failure of subsequent method calls such as toString() and divmod().
The attack vector is network-based, allowing remote attackers to leverage this flaw without requiring any user interaction. The required privileges are none, making it accessible to any user able to invoke the affected methods.
The attack complexity is low, as the vulnerability can be triggered through straightforward method calls. The integrity and confidentiality impacts are none, while the availability impact is low due to the potential for denial of service.
Risk & Impact Analysis
The real-world deployment risk associated with CVE-2026-2739 is characterized by the potential for service disruptions if the vulnerability is exploited. Organizations relying on bn.js for critical operations should recognize the implications of a denial of service, which can halt processes and impact user experience.
The blast radius of this vulnerability can be significant, especially in environments where bn.js is extensively utilized. With a CVSS score indicating medium severity, organizations should address this vulnerability in their priority patch cycle.
Organizations may schedule remediation to align with their regular maintenance cycles, ensuring that systems remain resilient against potential service outages.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
All versions of bn.js prior to 5.2.3 are affected by this vulnerability. Organizations should ensure they upgrade to version 5.2.3 or later to mitigate the risk.
Mitigation & Remediation
To mitigate the risks associated with CVE-2026-2739, organizations should update to bn.js version 5.2.3 or later. If patches are unavailable, consider implementing workarounds or configuration changes that limit exposure to this vulnerability.
Organizations may benefit from conducting an application security assessment to identify similar weaknesses across their systems.
Detection Guidance
Monitoring log indicators for unusual application behavior can help detect potential exploitation of this vulnerability. Look for signs of infinite loops or process hangs related to bn.js function calls.
Implementing network signatures that alert on abnormal bn.js usage patterns can also aid in early detection of exploitation attempts.
AppSecure Threat Intelligence Insight
CVE-2026-2739 represents a trend in dependency vulnerabilities that can lead to denial of service conditions. Security teams should remain vigilant about the libraries and packages they utilize in their applications.
To strengthen security postures, organizations should consider developing a comprehensive vulnerability management program that includes regular assessments and updates.
Additionally, adopting a proactive approach to penetration testing can help identify potential vulnerabilities before they are exploited.
Finally, keeping abreast of emerging security threats through resources like cloud security assessments will assist organizations in adapting to the evolving threat landscape.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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