Insertion of Sensitive Information Into Sent Data in Next.js - CVE-2026-119346
Published: November 4, 2026
Vulnerability identifier: #VU159262
CSH Severity: Medium
CVSS v4: 5.6 [CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-119346
CWE-ID: CWE-201
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose sensitive HttpOnly cookie values, including session tokens, through JavaScript running on the application's origin.
The vulnerability exists due to exposure of sensitive cookie data in a public response header in Next.js Edge runtime routes when setting cookies through NextResponse. A remote attacker can use JavaScript running on the same origin to read the internal x-middleware-set-cookie response header and obtain sensitive cookie values that would otherwise be inaccessible to JavaScript through the HttpOnly protection.
Affected software
Next.js
How to mitigate CVE-2026-119346
Install security update from vendor's website.
Next.js - addressed in versions 1.0.0, 1.0.1, 1.0.2, 1.1.0, 1.1.1, 1.1.2, 1.2.0, 1.2.1, 1.2.2, 1.2.3, 2.0.0, 2.0.1, 2.1.0, 2.1.1, 2.2.0, 2.3.0, 2.3.1, 2.3.2, 2.4.0, 7.0.0.0, 7.0.1.0, 15.5.29, 16.4.5