CVE-2026-12644
ts-deepmerge: Prototype Method Override leads to DoS
5.3
MEDIUM
CVSS 3.1
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.
How to fix CVE-2026-12644
To remediate CVE-2026-12644, upgrade the affected package to a fixed version below.
- npm/ts-deepmerge—upgrade to 8.0.0 or later
Is CVE-2026-12644 being exploited?
No exploitation signal available. Neither CISA KEV nor a current EPSS score has been published for CVE-2026-12644.
Affected packages (1)
- from 0, < 8.0.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P |
| osv | CVSS 3.1 | MEDIUM5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |