CVE-2026-4800
HighCVSS 8.1Exploitation Probability (EPSS)
High risk85th percentile - higher than 85% of all known CVEs
Summary
Lodash versions before 4.18.0 do not properly validate key names in the options.imports option of _.template. An attacker can inject default-parameter expressions that execute arbitrary code during template compilation. Additionally, prototype pollution can lead to similar attacks.
Risk Assessment
The organization is at risk of remote code execution if the application passes untrusted input as key names in options.imports. This could lead to server compromise or data exfiltration.
Recommendation
Upgrade Lodash to version 4.18.0 or later. As a workaround, do not pass untrusted input as key names in options.imports; use only static, developer-controlled key names.
Other vulnerabilities in Lodash
See all- CVE-2026-2950Medium
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 guarded against string key members, but an attacker can bypass it by using array-wrapped path segments. This allows deletion of properties from built-in prototypes like Object.prototype.
- CVE-2025-13465Medium
A vulnerability in Lodash versions 4.0.0 through 4.17.22 allows prototype pollution via the _.unset and _.omit functions. An attacker can pass crafted paths that cause Lodash to delete methods from global prototypes.
Original NVD description (English source)
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.