Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Lodash | Lodash | >= 4.0.0, < 4.18.0 |
| Lodash | Lodash-Amd | >= 4.0.0, < 4.18.0 |
| Lodash | Lodash-Es | >= 4.0.0, < 4.18.0 |
| Lodash | Lodash.Template | >= 4.0.0, < 4.18.0 |
Related Weaknesses (CWE)
References
- https://cna.openjsf.org/security-advisories.htmlThird Party Advisory
- https://github.com/advisories/GHSA-35jh-r3h4-6jhmNot Applicable
- https://github.com/lodash/lodash/commit/3469357cff396a26c363f8c1b5a91dde28ba4b1cNot Applicable
FAQ
What is CVE-2026-4800?
CVE-2026-4800 is a vulnerability with a CVSS score of 8.1 (HIGH). 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 ...
How severe is CVE-2026-4800?
CVE-2026-4800 has been rated HIGH with a CVSS base score of 8.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-4800?
Check the references section above for vendor advisories and patch information. Affected products include: Lodash Lodash, Lodash Lodash-Amd, Lodash Lodash-Es, Lodash Lodash.Template.