CVE-2026-4800
lodash vulnerable to Code Injection via `_.template` imports key names
Description
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. Workarounds: Do not pass untrusted input as key names in options.imports. Only use developer-controlled, static key names.
How to fix CVE-2026-4800
To remediate CVE-2026-4800, upgrade the affected package to a fixed version below.
- —no fix listed
- —upgrade to 4.18.0 or later
- —upgrade to 4.18.0 or later
- —upgrade to 4.18.0 or later
- —upgrade to 4.18.0 or later
Is CVE-2026-4800 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (5)
- from 0
- >= 4.0.0, < 4.18.0
- >= 4.0.0, < 4.18.0
- >= 4.0.0, < 4.18.0
- >= 4.0.0, < 4.18.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH8.1 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |