---
id: CVE-2025-13204
title: npm package `expr-eval` is vulnerable to Prototype Pollution
summary: >-
  npm package `expr-eval` is vulnerable to Prototype Pollution. An attacker with
  access to express eval interface can use JavaScript prototype-based
  inheritance model to achieve arbitrary code execution. The npm expr-eval-fork
  package reso…
severity: high
cvss: 7.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L'
cwe:
  - CWE-1321
vendor: silentmatt
product: javascript_expression_evaluator
affected:
  - javascript_expression_evaluator
published: '2025-11-14'
updated: '2026-10-07'
sourceUpdated: '2026-10-07T21:10:00.200'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-13204'
references:
  - url: >-
      https://github.com/SECCON/SECCON2022_final_CTF/blob/main/jeopardy/web/babybox/solver/solver.py
    label: cret@cert.org
  - url: 'https://github.com/jorenbroekema/expr-eval'
    label: cret@cert.org
  - url: 'https://github.com/silentmatt/expr-eval'
    label: cret@cert.org
  - url: 'https://github.com/silentmatt/expr-eval/pull/252/files'
    label: cret@cert.org
  - url: >-
      https://github.com/vladko312/extras/blob/f549d505af300fd74a01b46fab2102990ff1c14d/expr-eval.py
    label: cret@cert.org
  - url: 'https://www.huntr.dev/bounties/1-npm-expr-eval/'
    label: cret@cert.org
  - url: 'https://www.npmjs.com/package/expr-eval-fork'
    label: cret@cert.org
tags:
  - nvd
epss: 0.00452
epssPercentile: 0.37245
ingestedAt: '2026-10-07T21:54:15.040Z'
---

## Overview

npm package `expr-eval` is vulnerable to Prototype Pollution. An attacker with access to express eval interface can use JavaScript prototype-based inheritance model to achieve arbitrary code execution. The npm expr-eval-fork package resolves this issue.

## Affected

- `javascript_expression_evaluator`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.