Impact
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. 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.
Lodash versions 4.0.0 through 4.17.22 are vulnerable to prototype pollution in the .unset and .omit functions. 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.
This issue is patched on 4.17.23
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.
Impact
Lodash versions 4.0.0 through 4.17.22 are vulnerable to prototype pollution in the .unset and .omit functions. 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.
Patches
This issue is patched on 4.17.23.
Impact
Lodash versions 4.17.23 and earlier are vulnerable to prototype pollution in the .unset and .omit functions. 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.
Patches
This issue is patched in 4.18.0.
Workarounds
None. Upgrade to the patched version.
It was discovered that Lodash was vulnerable to a prototype pollution issue in the zipObjectDeep function. An attacker could possibly use this issue to modify application behavior. This issue only affected Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2020-8203) Liyuan Chen discovered that Lodash was vulnerable to a regular expression denial of service issue in the toNumber, trim, and trimEnd functions. An attacker could possibly use this issue to consume excessive system resources, resulting in a denial of service. This issue only affected Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2020-28500) Marc Hassan discovered that Lodash did not properly sanitize input to the template function. An attacker could possibly use this issue to inject and execute arbitrary commands. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS. (CVE-2021-23337) It was discovered that Lodash was vulnerable to a prototype pollution issue in the unset and omit functions. An attacker could possibly use this issue to delete properties from global prototypes, resulting in security restrictions being bypassed. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 25.10. (CVE-2025-13465) It was discovered that Lodash was vulnerable to a prototype pollution issue in the unset and omit functions. An attacker could possibly use this issue to delete properties from built-in prototypes, resulting in security restrictions being bypassed. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-2950) It was discovered that Lodash did not properly validate certain inputs to the template function. An attacker could possibly use this issue to inject malicious code during template processing, resulting in arbitrary code execution. (CVE-2026-4800)