How severe is CVE-2026-27942?

CVE-2026-27942 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-27942 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-27942?

CVE-2026-27942 affects Naturalintelligence Fast-xml-parser. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-27942?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-27942 have an EU (EUVD) identifier?

Yes. CVE-2026-27942 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8811.

When was CVE-2026-27942 published?

CVE-2026-27942 was published on 2026-02-26 and last updated on 2026-06-17.

CVE-2026-27942

CVE-2026-27942 is a high-severity vulnerability in Naturalintelligence Fast-xml-parser with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-120.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 2.7
EPSS exploit prediction: 0% (38th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-8811
Weakness: CWE-120
Affected product: Naturalintelligence Fast-xml-parser
Published: 2026-02-26
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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.
How severe is CVE-2026-27942?: CVE-2026-27942 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-27942 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-27942?: CVE-2026-27942 affects Naturalintelligence Fast-xml-parser. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-27942?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-27942 have an EU (EUVD) identifier?: Yes. CVE-2026-27942 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8811.
When was CVE-2026-27942 published?: CVE-2026-27942 was published on 2026-02-26 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:naturalintelligence:fast-xml-parser:*:*:*:*:*:*:*:*

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