CVE-2026-73569
fast-xml-parser entity-expansion flaw allows crafted XML to cause DoS.
Is CVE-2026-73569 being exploited?
Not confirmed. CVE-2026-73569 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 0.37% probability of exploitation in the next 30 days.
How severe is CVE-2026-73569?
CVE-2026-73569 is rated High. 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-2026-73569?
Yes. A fix has been recorded for CVE-2026-73569. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-73569 affect?
CVE-2026-73569 affects fast-xml-parser < 5.10.1 (introduced in 5.9.3), Node.js applications using fast-xml-parser for XML parsing. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-73569?
Upgrade fast-xml-parser to >=5.10.1; validate/limit XML input and enforce parsing timeouts.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attacker can send crafted XML with multiple DOCTYPEs to reset expansion limits, causing CPU exhaustion, event-loop blocking, memory exhaustion and process termination (DoS).
Patch when possible
- affected>= 5.9.3 and < 5.10.1
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.