Vulnerability in Naturalintelligence Fast-Xml-Parser
CVE-2026-126066
fast-xml-parser allows users to process XML from JS object without C/C++ based libraries or callbacks. Prior to 5.12.0, when the non-default stopNodes option is enabled, readStopNodeData() in OrderedObjParser.js calls readTagExp() for each less-than character in an unterminated stop-node body and repeatedly rescans the remaining input while looking for a closing greater-than character. An attacker who supplies XML containing many tag fragments without a later closing character can cause quadratic rescanning before parsing fails, blocking a Node.js event loop and causing CPU-exhaustion denial of service. This issue is fixed in version 5.12.0.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 3.7 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Naturalintelligence Fast-Xml-Parser — versions < 5.12.0
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-126066?
- CVE-2026-126066 is a low-severity vulnerability in Naturalintelligence Fast-Xml-Parser, classified under Inefficient Algorithmic Complexity. CVSS score: 3.7/10. Published 2026-11-10.
- How severe is CVE-2026-126066?
- Low severity. CVSS v3 base score is 3.7 out of 10.