CVE-2026-83605

xmldom: Attribute name injection via setAttribute() bypasses requireWellFormed

HIGH
8.7
CVSS Score
Published: September 1, 2026 at 02:18 PM UTC
Updated: September 8, 2026 at 09:29 PM UTC
1 product affected across 1 vendor@xmldom

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Severity
HIGH8.7
Exploit prediction
EPSS 0.6%
SSVC
PoC

Description

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. Prior to @xmldom/xmldom versions 0.8.14 and 0.9.11, and in xmldom version 0.6.0 and earlier, Element.setAttribute() calls the private _createAttribute(name) path without validating the attribute name, while Document.createAttribute(name) validates against QName. XMLSerializer.serializeToString() emits attribute names verbatim, and requireWellFormed: true did not validate them, so a crafted name can terminate the intended attribute and inject additional attributes, including event handlers, into browser-consumed output; synthesized xmlns:PREFIX declarations expose the same unchecked-name boundary. This issue is fixed in @xmldom/xmldom versions 0.8.14 and 0.9.11; no fixed version is available for xmldom.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.8.14v < 0.9.11<= 0.6.0
Affected range stops below 0.8.14, so it looks safe — our inference, not a vendor statement
Affected range stops below 0.9.11, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.7HIGHGitHub_M
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-91

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