CVE-2026-25896

CVE-2026-25896 is a critical-severity vulnerability in Naturalintelligence Fast-xml-parser with a CVSS 3.x base score of 9.3. 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-185.

Key facts

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. From 4.1.3to before 5.3.5, a dot (.) in a DOCTYPE entity name is treated as a regex wildcard during entity replacement, allowing an attacker to shadow built-in XML entities (<, >, &, ", ') with arbitrary values. This bypasses entity encoding and leads to XSS when parsed output is rendered. This vulnerability is fixed in 5.3.5.

Frequently asked questions

What is CVE-2026-25896?
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. From 4.1.3to before 5.3.5, a dot (.) in a DOCTYPE entity name is treated as a regex wildcard during entity replacement, allowing an attacker to shadow built-in XML entities (<, >, &, ", ') with arbitrary values. This bypasses entity encoding and leads to XSS when parsed output is rendered. This vulnerability is fixed in 5.3.5.
How severe is CVE-2026-25896?
CVE-2026-25896 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability none.
Is CVE-2026-25896 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-25896?
CVE-2026-25896 affects Naturalintelligence Fast-xml-parser. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-25896?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-25896 have an EU (EUVD) identifier?
Yes. CVE-2026-25896 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-7529.
When was CVE-2026-25896 published?
CVE-2026-25896 was published on 2026-02-20 and last updated on 2026-06-30.

References

Affected products (1)

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