Buffer overflow in Naturalintelligence Fast-Xml-Parser
CVE-2026-27942
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.007 (51.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 51.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.007 · change: +0.002
Affected products
- Naturalintelligence Fast-Xml-Parser — versions < 5.3.8
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-27942?
- CVE-2026-27942 is a high-severity vulnerability in Naturalintelligence Fast-Xml-Parser, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 7.5/10. Published 2026-02-26.
- How severe is CVE-2026-27942?
- High severity. CVSS v3 base score is 7.5 out of 10.