lodash vulnerable to Code Injection via `_.template` imports key names
The fix for CVE-2021-23337 added validation for the variable option in _.template but did not apply the same validation to options.imports key names, and 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, so if Object.prototype has been polluted by another vector the polluted keys are copied into the imports object and passed to Function(). The
lodash vulnerable to Prototype Pollution via array path bypass in `_.unset` and `_.omit`
The _.unset and _.omit functions in Lodash are vulnerable to prototype pollution. The fix for CVE-2025-13465 only guards against string key members, so an attacker can bypass the check by passing array-wrapped path segments. This allows deletion of properties from built-in prototypes such as Object.prototype, Number.prototype, and String.prototype. The issue permits deletion of prototype properties but does not allow overwriting their original behavior. The issue is patched from 4.18.0 to 4.18.1 depending on the package: lodash, lodash-es, and lodash-amd in 4.18.1, and the standalone lodash.unset and lodash.omit packages in 4.18.0.
Prototype Pollution Vulnerability in Lodash _.unset and _.omit functions
The _.unset and _.omit functions in Lodash are vulnerable to prototype pollution. An attacker can pass crafted paths which cause Lodash to delete methods from global prototypes. The issue permits deletion of properties but does not allow overwriting their original behavior. The issue is patched from 4.17.23 to 4.18.0 depending on the package: lodash, lodash-es, and lodash-amd in 4.17.23, and the standalone lodash.unset and lodash.omit packages in 4.18.0.
Versions of lodash lower than 4.17.12 are vulnerable to Prototype Pollution. The function defaultsDeep could be tricked into adding or modifying properties of Object.prototype using a constructor payload.
lodash prior to 4.17.11 is affected by: CWE-400: Uncontrolled Resource Consumption. The impact is: Denial of service. The component is: Date handler. The attack vector is: Attacker provides very long strings, which the library attempts to match using a regular expression. The fixed version is: 4.17.11.
A prototype pollution vulnerability was found in lodash <4.17.11 where the functions merge, mergeWith, and defaultsDeep can be tricked into adding or modifying properties of Object.prototype.
lodash node module before 4.17.5 suffers from a Modification of Assumed-Immutable Data (MAID) vulnerability via defaultsDeep, merge, and mergeWith functions, which allows a malicious user to modify the prototype of "Object" via __proto__, causing the addition or modification of an existing property that will exist on all objects.