Vulnerability · Published Nov 23, 2020 · Assigned by snyk

CVE-2020-7777Arbitrary Code Execution

High 7.2

In plain English

A high-severity security flaw in jsen. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 2.1% (higher than 82% of all known vulnerabilities).

Severity (CVSS 3.1)7.2High

Exploit odds (30 days)2.1%top 18.1% of all CVEs

Exploited in the wildNo reportsnot in CISA KEV

Attack toolingNoneno public tooling known

Official description

This affects all versions of package jsen. If an attacker can control the schema file, it could run arbitrary JavaScript code on the victim machine. In the module description and README file there is no mention about the risks of untrusted schema files, so I assume that this is applicable. In particular the required field of the schema is not properly sanitized. The resulting string that is build based on the schema definition is then passed to a Function.apply();, leading to an Arbitrary Code Execution.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	jsen	no fix listed	GHSA-vm64-cfqx-3698

Affected products (as reported)

Vendor	Product	Versions
n/a	jsen	0 – before unspecified

References

https://snyk.io/vuln/SNYK-JS-JSEN-1014670 x_refsource_MISC
https://github.com/bugventure/jsen/blob/master/lib/jsen.js%23L875 x_refsource_MISC