GitHub Advisoryadvisory · npm

GHSA-hf2r-9gf9-rwch Convict has prototype pollution via load(), loadFile(), and schema initialization

CRITICAL Published 2026-03-26 Modified 2026-03-26 Official page ↗
Aliases
CVE-2026-33863
Ecosystem
npm
Packages
convict
Severity
Critical
CVSS vector
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Weaknesses
CWE-1321
Reviewed
2026-03-26

Affected packages

• npm convict: < 6.2.5 → fixed in 6.2.5

Description

Impact Two unguarded prototype pollution paths exist, not covered by previous fixes: 1. `config.load()` / `config.loadFile()` — `overlay()` recursively merges config data without checking for forbidden keys. Input containing` __proto__` or `constructor.prototype` (e.g. from a JSON file) causes the recursion to reach `Object.prototype` and write attacker-controlled values onto it. 2. Schema initialization — passing a schema with `constructor.prototype.*` keys to `convict({...})` causes default-value propagation to write directly to `Object.prototype` at startup. Depending on how polluted properties are consumed, impact ranges from unexpected behavior to authentication bypass or RCE. Workarounds Do not pass untrusted data to load(), loadFile(), or convict(). Resources Prior advisory: GHSA-44fc-8fm5-q62h Related issue: https://github.com/mozilla/node-convict/issues/423

Related

Alias · not in database (1)

Weakness · CWE (1)

  • CWE-1321 Improperly Controlled Modification of Object Prototype Attributes weakness

References