How severe is CVE-2026-25128?

CVE-2026-25128 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-2026-25128 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-25128?

CVE-2026-25128 affects Naturalintelligence Fast-xml-parser. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-25128?

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-2026-25128 have an EU (EUVD) identifier?

Yes. CVE-2026-25128 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-5026.

When was CVE-2026-25128 published?

CVE-2026-25128 was published on 2026-01-30 and last updated on 2026-06-17.

CVE-2026-25128

CVE-2026-25128 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-20.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-5026
Weakness: CWE-20
Affected product: Naturalintelligence Fast-xml-parser
Published: 2026-01-30
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. In versions 5.0.9 through 5.3.3, a RangeError vulnerability exists in the numeric entity processing of fast-xml-parser when parsing XML with out-of-range entity code points (e.g., `&#9999999;` or `&#xFFFFFF;`). This causes the parser to throw an uncaught exception, crashing any application that processes untrusted XML input. Version 5.3.4 fixes the issue.

Frequently asked questions

What is CVE-2026-25128?: 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. In versions 5.0.9 through 5.3.3, a RangeError vulnerability exists in the numeric entity processing of fast-xml-parser when parsing XML with out-of-range entity code points (e.g., `&#9999999;` or `&#xFFFFFF;`). This causes the parser to throw an uncaught exception, crashing any application that processes untrusted XML input. Version 5.3.4 fixes the issue.
How severe is CVE-2026-25128?: CVE-2026-25128 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-2026-25128 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-25128?: CVE-2026-25128 affects Naturalintelligence Fast-xml-parser. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-25128?: 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-2026-25128 have an EU (EUVD) identifier?: Yes. CVE-2026-25128 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-5026.
When was CVE-2026-25128 published?: CVE-2026-25128 was published on 2026-01-30 and last updated on 2026-06-17.

References

Affected products (1)

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

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