CVE-2026-4800 — lodash vulnerable to Code Injection via `_.template` imports key names

Description (CNA)

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 issue is fixed in 4.18.1 for lodash, lodash-es, lodash-amd, and lodash.template. As a workaround, do not pass untrusted input as key names in options.imports; use only developer-controlled, static key names.

Affected (CNA)

Vendor / product	Versions
lodash / lodash	affected 4.0.0 before 4.18.1; unaffected 4.18.1
lodash / lodash-es	affected 4.0.0 before 4.18.1; unaffected 4.18.1
lodash / lodash-amd	affected 4.0.0 before 4.18.1; unaffected 4.18.1
lodash / lodash.template	affected 4.0.0 before 4.18.1; unaffected 4.18.1

CWE

CWE-94

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.

redhat-SADP

A flaw was found in lodash. 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. 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().