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GHSA-x3cc-x39p-42qx

MediumCVSS 6.5 / 10
Published Jun 13, 2023·Last modified Mar 16, 2026
Affected Components(0)

No affected components available

Description

Impact

As a part of this vulnerability, user was able to se code using __proto__ as a tag or attribute name.

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

Risk Scores
Base Score
6.5

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information.

Threat Intelligence
6.0

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
9.88%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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