NanaZip, an open source file archive tool, has a denial-of-service vulnerability affecting versions 5.0.1252.0 through 6.0.1638.0 and 6.5.1638.0. The vulnerability exists in the .NET Single File Application parser, where a crafted bundle can exploit an integer underflow in header-size calculation. This could lead to an unbounded memory allocation attempt during the opening of an archive, resulting in a denial of service.
The CVSS score for this vulnerability is 5.1, categorized as medium severity. Organizations using the affected versions are at risk of interruptions as the vulnerability may allow an attacker to exhaust system resources. It is crucial for users of NanaZip to promptly update to versions 6.0.1638.0 or 6.5.1638.0, which contain the necessary patches to mitigate this issue.
Current exploitation status indicates that there are no known exploits available for this vulnerability. However, given the nature of the denial-of-service attack, it is imperative for organizations to remain vigilant and apply the recommended updates to ensure system stability.
Organizations should prioritize patching immediately to safeguard against potential disruptions. Additionally, monitoring for any unusual activity related to the use of NanaZip may provide further protection against opportunistic attacks.
Vulnerability Details
According to the official CVE description, the vulnerability allows for a denial-of-service condition via an integer underflow in header-size calculations. The affected product is NanaZip, developed by m2team. The vulnerability was published on February 26, 2026. The relevant Common Weakness Enumeration (CWE) classification is CWE-191.
The CVSS vector string is as follows: CVSS:4.0/AV:L/AC:L/PR:L/UI:P/VC:N/VI:N/VA:H. This indicates a local attack vector with low complexity and low privileges required, highlighting the need for user interaction.
Technical Analysis
The root cause of this vulnerability lies in the header-size calculation within the .NET Single File Application parser of NanaZip. When processing crafted bundles, the integer underflow can occur, leading to excessive memory allocation and ultimately causing a denial-of-service condition.
The attack vector is local, meaning that an attacker must have access to the system where NanaZip is installed. The attack complexity is low, as it does not require sophisticated methods to exploit the vulnerability. The privileges required to exploit this vulnerability are low, meaning that even unprivileged users could potentially trigger an attack.
User interaction is required, as the crafted bundle must be opened by the user. The impact on availability is high, as the denial-of-service condition could render the application inoperable. However, there is no impact on confidentiality or integrity.
Risk & Impact Analysis
The real-world risk associated with this vulnerability is significant, as it could lead to service downtime for organizations relying on NanaZip for file archiving. The potential for unbounded memory allocation can exhaust system resources, leading to application crashes and service interruptions.
Organizations should assess the urgency of this issue based on their usage of the affected versions. The presence of this vulnerability in production environments poses a risk to operational continuity. As such, organizations must address this vulnerability in their priority patch cycle.
Given that the CVSS score falls within the medium severity range, organizations should schedule remediation according to their patch management policies. The potential blast radius of this vulnerability could impact any systems utilizing NanaZip for file handling.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerable versions of NanaZip include all versions from 5.0.1252.0 up to, but not including, 6.0.1638.0. Organizations using these versions should upgrade to at least 6.0.1638.0 or 6.5.1638.0 to mitigate the risk associated with this vulnerability.
Mitigation & Remediation
To remediate this vulnerability, organizations should upgrade to the fixed versions of NanaZip: 6.0.1638.0 or 6.5.1638.0. If a patch is not immediately available, consider implementing configuration hardening to minimize exposure.
For continuous monitoring and proactive security measures, organizations may consider using continuous penetration testing to identify any similar vulnerabilities.
Detection Guidance
Organizations should monitor logs for any anomalies during the opening of archive files, specifically for signs of excessive memory usage which could indicate an attempt to exploit this vulnerability.
Additionally, behavioral monitoring should be implemented to detect unusual patterns of archive processing which could signal an exploit attempt.
AppSecure Threat Intelligence Insight
The significance of this vulnerability lies in its potential to disrupt operations for users of NanaZip. As the landscape of denial-of-service vulnerabilities evolves, it is crucial for organizations to adopt proactive measures to mitigate risks.
Security teams should draw lessons from this incident, emphasizing the importance of timely updates and vigilant monitoring of software dependencies. For more extensive penetration testing practices, organizations can refer to the penetration testing methodology to ensure comprehensive coverage against vulnerabilities.
In addition, organizations should consider the implications of vulnerabilities like CVE-2026-27710 in the context of broader security strategies, such as adopting a vulnerability management program that encompasses regular assessments and updates.
Lastly, understanding the evolution of denial-of-service vulnerabilities can aid organizations in preparing for future threats. The insights gleaned from this analysis can serve as a foundation for enhancing overall security posture.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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