CVE-2026-83609
XML DOM parser accepts multiline QNames enabling markup injection on serialization.
Is CVE-2026-83609 being exploited?
Not confirmed. CVE-2026-83609 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.33% probability of exploitation in the next 30 days.
How severe is CVE-2026-83609?
CVE-2026-83609 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-83609?
Yes. A fix has been recorded for CVE-2026-83609. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-83609 affect?
CVE-2026-83609 affects @xmldom/xmldom <0.9.12, xmldom 0.9.0-0.9.11, Node.js apps and libraries that bundle xmldom. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-83609?
Upgrade to @xmldom/xmldom 0.9.12; audit and rebuild dependent projects.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attacker can craft element/attribute names with line breaks to inject arbitrary XML markup during serialization, enabling XML/markup injection and downstream attacks.
Patch when possible
- affected>= 0.9.0 and < 0.9.12
- affected>= 0.9.0 and < 0.9.12
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.