CVE-2026-27942: CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') in NaturalIntelligence fast-xml-parser
fast-xml-parser allows users to validate XML, parse XML to JS object, or build XML from JS object without C/C++ based libraries and no callback. Prior to version 5.3.8, the application crashes with stack overflow when user use XML builder with `preserveOrder:true`. Version 5.3.8 fixes the issue. As a workaround, use XML builder with `preserveOrder:false` or check the input data before passing to builder.
AI Analysis
Technical Summary
CVE-2026-27942 is a classic buffer overflow vulnerability (CWE-120) in the fast-xml-parser library by NaturalIntelligence. The vulnerability triggers a stack overflow crash when the XML builder is used with the preserveOrder:true option in versions before 5.3.8. This occurs because the application copies input data without properly checking its size. The issue is fixed in version 5.3.8.
Potential Impact
The vulnerability can cause the application to crash due to stack overflow when processing XML with preserveOrder:true, potentially leading to denial of service. There is no indication of code execution or data corruption beyond the crash. The CVSS score is low (2.7), reflecting limited impact and no known exploitation in the wild.
Mitigation Recommendations
Upgrade to fast-xml-parser version 5.3.8 or later, which contains the official fix for this vulnerability. As a temporary workaround, avoid using the XML builder with preserveOrder:true or validate input data before passing it to the builder to prevent triggering the overflow.
CVE-2026-27942: CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') in NaturalIntelligence fast-xml-parser
Description
fast-xml-parser allows users to validate XML, parse XML to JS object, or build XML from JS object without C/C++ based libraries and no callback. Prior to version 5.3.8, the application crashes with stack overflow when user use XML builder with `preserveOrder:true`. Version 5.3.8 fixes the issue. As a workaround, use XML builder with `preserveOrder:false` or check the input data before passing to builder.
CVSS v4.0
Score 2.7low
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-27942 is a classic buffer overflow vulnerability (CWE-120) in the fast-xml-parser library by NaturalIntelligence. The vulnerability triggers a stack overflow crash when the XML builder is used with the preserveOrder:true option in versions before 5.3.8. This occurs because the application copies input data without properly checking its size. The issue is fixed in version 5.3.8.
Potential Impact
The vulnerability can cause the application to crash due to stack overflow when processing XML with preserveOrder:true, potentially leading to denial of service. There is no indication of code execution or data corruption beyond the crash. The CVSS score is low (2.7), reflecting limited impact and no known exploitation in the wild.
Mitigation Recommendations
Upgrade to fast-xml-parser version 5.3.8 or later, which contains the official fix for this vulnerability. As a temporary workaround, avoid using the XML builder with preserveOrder:true or validate input data before passing it to the builder to prevent triggering the overflow.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-02-25T03:11:36.689Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 699fabd8b7ef31ef0b7dea09
Added to database: 02/26/2026, 02:11:36 UTC
Last enriched: 06/24/2026, 15:07:51 UTC
Last updated: 07/31/2026, 19:22:58 UTC
Views: 346
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