PoC Index

CVE-2026-25896

CRITICAL 9.3EPSS 0.5%

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.

CVSS v3.1
7.1 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
CVSS v3.1
9.3 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N
CVSS v3.1
9.3 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N
EPSS
0.46% chance of exploitation in the next 30 days, 38th percentile
Published
2026-02-20
Updated
2026-08-24

Proof-of-concept exploits (1)

References

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