CVE-2026-83617Public exploitNetwork attack vectorHinoki check available

XML injection via multiline QName validation bypass

Published Sep 1, 2026 · Updated Sep 1, 2026

XML injection in XMLSerializer in xmldom 0.9.11 allows remote attackers to alter serialized markup via crafted DOM names. The QName_exact check inherits the multiline flag from lib/grammar.js, so it validates only a conforming first line and serializes trailing breakout markup verbatim. Exploitation requires an application to construct element or attribute names from untrusted input and serialize them with requireWellFormed enabled; successful attacks modify XML structure and can cause downstream XSS in HTML contexts.

CVSS severity8.7
High
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

XML injection in XMLSerializer in xmldom 0.9.11 allows remote attackers to alter serialized markup via crafted DOM names. The QName_exact check inherits the multiline flag from lib/grammar.js, so it validates only a conforming first line and serializes trailing breakout markup verbatim. Exploitation requires an application to construct element or attribute names from untrusted input and serialize them with requireWellFormed enabled; successful attacks modify XML structure and can cause downstream XSS in HTML contexts.

The record

CVE
CVE-2026-83617
Published
Sep 1, 2026
Updated
Sep 1, 2026
Vendor
xmldom
Product
xmldom
Classifications
CWE-625, CWE-91
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

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

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=>= 0.9.11, < 0.9.12

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

xmldom · xmldomversion=>= 0.9.11, < 0.9.12

Published CVSS scores

8.7GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-625Permissive Regular Expression
CWE-91XML Injection (aka Blind XPath Injection)

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo