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CVE-2026-73569Suited to automated attack · CISA

fast-xml-parser: Repeated DOCTYPE declarations reset entity expansion limits

CVSS score

8.7

EPSS probability

%0.5

Risk score

0.0

Published

1 mo ago

OverviewPublic Exploits (0)NewsroomVulnerability Timeline
Official patch verified

Etkilenen ürün ve sürüm için yayımlanan güvenlik güncellemesini uygulayın.

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Vulnerability description

DayBreach CVE AI Research

CVE-2026-73569 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

fast-xml-parser allows users to process XML from JS object without C/C++ based libraries or callbacks. From 5.9.3 until 5.10.1, src/xmlparser/OrderedObjParser.js processes multiple DOCTYPE declarations within a single XML document and passes each declaration's entities through addInputEntities(). addInputEntities() resets maxTotalExpansions and maxExpandedLength every time it is called, allowing additional DOCTYPE declarations to repeatedly reset the configured entity-expansion limits during one parse operation. A crafted XML document can then cause excessive CPU use, event-loop blocking, memory exhaustion, and process termination. This issue is fixed in version 5.10.1.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-73569 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1naturalintelligencefast-xml-parser View
2npmfast-xml-parser View
3npmfast-xml-parser View
Total affected vendors: 2|Products: 3

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
8.7CVSS 4.0—Vector not publishedGitHub Advisory
8.7CVSS V4_0HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NCVE CNA
8.7CVSS V40HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XNVD

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

1 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

osvfast-xml-parser5.10.1

OSV düzeltilmiş sürüm: 5.10.1

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Apply the official update named in the evidence only to the matching product and version.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-73569 is associated with the following CWEs:

CWE-776: Common Weakness Enumeration Entry CWE-776

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-73569 weaknesses.

CAPEC-66: SQL InjectionCAPEC-126: Path TraversalCAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsGerekmiyor
UserGerekmiyor

Official Sources and Advisories

https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-8r6m-32jq-jx6qvendor-advisoryhttps://github.com/NaturalIntelligence/fast-xml-parser/commit/4e546e03987662de5495d050b5fba26bea65383fvendor-advisoryhttps://github.com/NaturalIntelligence/fast-xml-parser/releases/tag/v5.10.1vendor-advisoryhttps://github.com/advisories/GHSA-8r6m-32jq-jx6qvendor-advisoryhttps://github.com/NaturalIntelligence/fast-xml-parservendor-advisory

CVSS Vector Radar Chart

8.7 / 10
Attack VectorNetworkComplexityLowPrivilegesNoneUser Interact.NoneConfidentialityLowIntegrityNoneAvailabilityHigh

Vulnerability Scoring Details

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
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone required
User InteractionNone required
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)None
Availability (Erişilebilirlik)High

Yama doğrulandı

1 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

Follow the vendor

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naturalintelligence
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npm

Weakness Type (CWE & CAPEC)

CWE-776

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CVE-2026-73569 · fast-xml-parser: Repeated DOCTYPE declarations reset entity expansion limits · DayBreach