Bug 2435497 (CVE-2026-25128)

Summary: CVE-2026-25128 fast-xml-parser: fast-xml-parser has RangeError DoS Numeric Entities Bug
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: abarbaro, abuckta, alizardo, anjoseph, anthomas, caswilli, dkuc, ehelms, fdeutsch, ggainey, jchui, jhe, jprabhak, juwatts, kaycoth, kshier, ktsao, manissin, mhulan, nboldt, nmoumoul, orabin, oramraz, osousa, pcreech, psrna, rchan, rjohnson, smallamp, smullick, stcannon, stirabos, teagle, thason, tmalecek, wtam
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A denial of service flaw has been discovered in the fast-xml-parser npm library. In fast-xml-parser, 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.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2435526, 2435527    
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Description OSIDB Bzimport 2026-01-30 16:01:50 UTC 
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 4.3.6 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.