CVE-2026-26021

Description

set-in provides the set value of nested associative structure given array of keys. A prototype pollution vulnerability exists in the the npm package set-in (>=2.0.1, < 2.0.5). Despite a previous fix that attempted to mitigate prototype pollution by checking whether user input contained a forbidden key, it is still possible to pollute Object.prototype via a crafted input using Array.prototype. This has been fixed in version 2.0.5.

Weakness classification

• security-advisories@github.com: CWE-1321

Primary references

• security-advisories@github.com — Patch
• security-advisories@github.com — Exploit, Vendor Advisory