CVE-2026-44664Network attack vector

XML injection via incomplete comment sanitization

Published May 13, 2026 · Updated May 13, 2026

XML injection in Natural Intelligence fast-xml-builder 1.1.5 allows remote attackers to inject XML or HTML through comment values. The comment builder replaces each double dash only once, so overlapping dashes leave a closing delimiter that terminates the comment early. Exploitation requires an application to enable comment properties, accept attacker-controlled values, and expose the generated output to a user; injected markup can alter that output or execute script in an HTML consumer.

CVSS severity6.1
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

XML injection in Natural Intelligence fast-xml-builder 1.1.5 allows remote attackers to inject XML or HTML through comment values. The comment builder replaces each double dash only once, so overlapping dashes leave a closing delimiter that terminates the comment early. Exploitation requires an application to enable comment properties, accept attacker-controlled values, and expose the generated output to a user; injected markup can alter that output or execute script in an HTML consumer.

The record

CVE
CVE-2026-44664
Published
May 13, 2026
Updated
May 13, 2026
Vendor
Natural Intelligence
Product
fast-xml-builder
Classifications
CWE-91, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 13, 2026CVE publishedPublication date reported by the CVE source.
  2. May 13, 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=1.1.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Natural Intelligence · fast-xml-builderversion=1.1.5

Published CVSS scores

6.1GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-91XML Injection (aka Blind XPath Injection)
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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