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CVE-2026-4800

CRITICAL CVSS 3.1: 9.8 EPSS 0.09%
Updated Apr 07, 2026
Lodash
Parameter Value
CVSS 9.8 (CRITICAL)
Affected Versions before 4.5.0
Fixed In 4.18.0
Type CWE-94 (Code Injection)
Vendor Lodash
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service

CVSS Vector v3.1

Weakness Type (CWE)

Vulnerable Products 4

Configuration From (including) Up to (excluding)
Lodash Lodash
cpe:2.3:a:lodash:lodash:*:*:*:*:*:node.js:*:*
4.17.21
Lodash Lodash-Es
cpe:2.3:a:lodash:lodash-es:*:*:*:*:*:node.js:*:*
4.17.21
Lodash Lodash-Rails
cpe:2.3:a:lodash:lodash-rails:*:*:*:*:*:ruby:*:*
4.17.21
Lodash Lodash.Template
cpe:2.3:a:lodash:lodash.template:*:*:*:*:*:node.js:*:*
<= 4.5.0

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