GHSA-x3cc-x39p-42qx

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    GHSA-x3cc-x39p-42qx

    Published: 13 Jun 2023Last Modified: 8 Jul 2026

    Summary: fast-xml-parser vulnerable to Prototype Pollution through tag or attribute name

    Details: ### Impact As a part of this vulnerability, user was able to se code using `__proto__` as a tag or attribute name. ```js const { XMLParser, XMLBuilder, XMLValidator} = require("fast-xml-parser"); let XMLdata = "<__proto__><polluted>hacked</polluted></__proto__>" const parser = new XMLParser(); let jObj = parser.parse(XMLdata); console.log(jObj.polluted) // should return hacked ``` ### Patches The problem has been patched in v4.1.2 ### Workarounds User can check for "__proto__" in the XML string before parsing it to the parser. ### References https://gist.github.com/Sudistark/a5a45bd0804d522a1392cb5023aa7ef7

    Affected packages

    Package

    Name: fast-xml-parser

    Purl: pkg:npm/fast-xml-parser

    Affected ranges

    Type: SEMVER

    Events:

    Introduced- 0
    Fixed -4.1.2

    Affected versions

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    GHSA-x3cc-x39p-42qx | CVE-DB