Prototype Pollution in Ahdinosaur Set-in

CVE-2026-26021

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 pol…

Vulnerability class: Prototype Pollution

EPSS: 0.005 (36.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-26021?
CVE-2026-26021 is a critical-severity vulnerability in Ahdinosaur Set-in, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 9.8/10. Published 2026-02-11.
How severe is CVE-2026-26021?
Critical severity. CVSS v3 base score is 9.8 out of 10.