CVE-2026-12644
Medium
Description
Versions of the package ts-deepmerge before 8.0.0 are vulnerable to Uncaught Exception due to the improper handling of built-in Object.prototype methods (such as toString, valueOf). When user-controlled input contains these keys with non-function values, the resulting merged object becomes broken — any string context operation throws a TypeError, crashing the application.
SeverityMedium
CVSS5.3
Exploit probability—
ProductTs-deepmerge
PublishedJun 19, 2026
First seenJun 19, 2026
Weakness typeCWE-248CWE-248
How to fix
Update
- ts-deepmerge8.0.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| ts-deepmergenpm | v < 8.0.0 | 8.0.0 |
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