Prototype pollution in JavaScript Cookie - CVE-2026-46625
Published: July 26, 2026
Vulnerability identifier: #VU139385
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-46625
CWE-ID: CWE-1321
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: js-cookie
Affected software:
JavaScript Cookie
JavaScript Cookie
Detailed vulnerability description
The vulnerability allows a remote attacker to inject cookie attributes.
The vulnerability exists due to improperly controlled modification of object prototype attributes in the assign() helper when processing a JSON-derived attributes object. A remote attacker can supply a specially crafted object containing a __proto__ property to inject cookie attributes.
This issue affects applications that pass attacker-influenced JSON-derived objects as the attributes argument to Cookies.set, Cookies.remove, Cookies.withAttributes, or Cookies.withConverter.
How to mitigate CVE-2026-46625
Install security update from vendor's website.