SB2026110472 - XML Entity Expansion in fast-xml-parser

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Main Vulnerability Database SB2026110472

SB2026110472 - XML Entity Expansion in fast-xml-parser

Published: November 4, 2026

Security Bulletin ID SB2026110472
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) XML Entity Expansion (CVE-ID: CVE-2026-73569)

CWE-ID: CWE-776 - Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service through excessive CPU consumption, event-loop blocking, memory exhaustion, or process termination.

The vulnerability exists due to improper enforcement of XML entity expansion limits in fast-xml-parser and the addInputEntities() function of @nodable/entities when processing multiple DOCTYPE declarations within a single XML document. A remote attacker can supply a crafted XML document containing repeated DOCTYPE declarations to reset the maxTotalExpansions and maxExpandedLength counters during parsing, exceed the configured limits, and cause a denial of service.


Remediation

Install update from vendor's website.

References