lodash vulnerable to Code Injection via `_.template` imports key names

### Impact The fix for [CVE-2021-23337](https://github.com/advisories/GHSA-35jh-r3h4-6jhm) added validation for the `variable` option in `_.template` but did not apply the same validation to `options.imports` key names. Both paths flow into the same `Function()` constructor sink. When an application passes untrusted input as `options.imports` key names, an attacker can inject default-parameter expressions that execute arbitrary code at template compilation time. Additionally, `_.template` uses `assignInWith` to merge imports, which enumerates inherited properties via `for..in`. If `Object.prototype` has been polluted by any other vector, the polluted keys are copied into the imports object and passed to `Function()`. ### Patches Users should upgrade to version 4.18.0. The fix applies two changes: 1. Validate `importsKeys` against the existing `reForbiddenIdentifierChars` regex (same check already used for the `variable` option) 2. Replace `assignInWith` with `assignWith` when merging imports, so only own properties are enumerated ### Workarounds Do not pass untrusted input as key names in `options.imports`. Only use developer-controlled, static key names.

Source published

1 Apr 2026 23:51:12 UTC

Source modified

17 Oct 2026 02:56:15 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Publisher rating · HIGH