NexaPulse
Subscribe
7.5highHigh

CVE-2026-26278

Naturalintelligence Fast-Xml-Parser

fast-xml-parser allows users to validate XML, parse XML to JS object, or build XML from JS object without C/C++ based libraries and no callback. In versions 4.1.3 through 5.3.5, the XML parser can be forced to do an unlimited amount of entity expansion. With a very small XML input, it’s possible to make the parser spend seconds or even minutes processing a single request, effectively freezing the application. Version 5.3.6 fixes the issue. As a workaround, avoid using DOCTYPE parsing by `processEntities: false` option.

Exploitation status

  • Published references include exploit or proof-of-concept material. There is no confirmation it is being used in real attacks.
  • A vendor advisory or patch reference has been published.

What the metrics mean

  • It is reachable over a network, without needing local access.
  • For an attacker who can reach it, no special conditions are needed to exploit it.
  • To exploit it, no account is needed.
  • Beyond that, no action by a user is required.

Scoring

CVSS
7.5 (v3.1)
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-776
Assigned by
security-advisories@github.com

Dates

Published
2026-02-19
Last modified
2026-08-26
Sources
NVD

Affected products

  • Naturalintelligence Fast-Xml-Parser4.1.3 - 5.3.6

As listed in the NVD configuration data. Not a statement about your estate.

References