CVE intelligence and bounded remediation

CVE-2020-7777 — This affects all versions of package jsen

High CVSS 7.2

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.

Severity
High
CVSS
7.2 (3.1)
Published
2020-11-23
CISA KEV
Not currently listed
Ecosystem
javascript/npm

Affected products

  • jsen_project / jsen

Matched remediation archetype

Command, code, expression, and template injection

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace untrusted values to process execution, interpreters, evaluators, template engines, dynamic imports, and administrative scripting features.
  • Determine whether the affected path is reachable across each trust boundary and which service account or host privilege it inherits.
  • Review configuration for optional execution features, unsafe compatibility modes, and shell invocation.

Remediate safely

  • Replace string-built commands or evaluated code with fixed operations and structured argument APIs that do not invoke a shell.
  • Use strict allowlists for operation identifiers and reject unexpected input before it reaches any interpreter.
  • Update the affected component and add inert regression tests covering metacharacters, encoding variants, and alternate request paths.

Authoritative sources

Complete CVE record and remediation plan

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