CVE-2026-27942Public exploitNetwork attack vector

Application crash via recursive non-array XMLBuilder input

Published Feb 26, 2026 · Updated Feb 26, 2026

Denial of service in Natural Intelligence fast-xml-parser allows remote attackers to crash applications via crafted XMLBuilder input. With preserveOrder enabled, orderedJs2Xml arrToStr treats a non-array child string as an array and recursively processes the same character until the stack overflows. Exploitation requires a consuming application to pass attacker-controlled JavaScript object data to XMLBuilder; the affected process terminates without reported data disclosure or modification.

CVSS severity7.5
High
EPSS probability0.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Natural Intelligence fast-xml-parser allows remote attackers to crash applications via crafted XMLBuilder input. With preserveOrder enabled, orderedJs2Xml arrToStr treats a non-array child string as an array and recursively processes the same character until the stack overflows. Exploitation requires a consuming application to pass attacker-controlled JavaScript object data to XMLBuilder; the affected process terminates without reported data disclosure or modification.

The record

CVE
CVE-2026-27942
Published
Feb 26, 2026
Updated
Feb 26, 2026
Vendor
Natural Intelligence
Product
fast-xml-parser
Classifications
CWE-120, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 26, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 5.3.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Natural Intelligence · fast-xml-parserversion=< 5.3.8

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
2.7GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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