CVE-2026-46625

Description

JavaScript Cookie: Per-instance prototype hijack in assign() enables cookie-attribute injection

Overview

State

—

Assigner (CNA)

—

CVSS severity

high

CVSS score

7.5 / 10

CVSS vector

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Effective score

7.5 / 10 HIGH source: CNA overview

CWE(s)

—

Reserved

—

Published

—

Last updated

—

Source

https://www.tenable.com/cve/CVE-2026-46625

Linked Threat

CVE-2026-46625 — CVE-2026-46625

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID

EUVD-2026-36154

Assigner

GitHub_M

Published

Jun 10, 2026, 9:18:05 PM

Updated

Aug 13, 2026, 12:04:30 PM

EUVD base score (CVSS 3.1)

7.5 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EUVD-reported EPSS

0.5100

Vendors

js-cookie

Products

js-cookie (< 3.0.7)

Aliases

GHSA-qjx8-664m-686j

ENISA description: JavaScript Cookie is a JavaScript API for handling cookies, client-side. Prior to version 3.0.7, js-cookie's internal assign() helper copies properties with for...in + plain assignment. When the source object is produced by JSON.parse, the JSON object's "__proto__" member is an own enumerable property, so the for…in enumerates it and the target[key] = source[key] write triggers the Object.prototype.__proto__ setter on the fresh target ({}). The result is a per-instance prototype hijack: Object.prototype itself is untouched, but the merged attributes object now inherits attacker-controlled keys. Because the consuming set() function then enumerates the merged object with another for...in, every key the attacker placed on the polluted prototype lands in the resulting Set-Cookie string as an attribute pair. The attacker can set domain=, secure=, samesite=, expires=, and path= on cookies whose attributes the developer thought were locked down. This issue has been patched in version 3.0.7.

Vendor references (0)

References embedded in the original CVE record by the assigning CNA.

None in the CVE record.

Web references (2)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

• https://nvd.nist.gov/vuln/detail/CVE-2026-46625 tenable:nvd.nist.gov
• https://www.cve.org/CVERecord?id=CVE-2026-46625 tenable:www.cve.org

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

• THREAT ADVISORY RedSun Zero-Day (Windows Defender) April 17, 2026
  web:blackswan-cybersecurity.com

  Cloud Files API activity originating outside legitimate OneDrive/sync processes. Mitigation Steps: Apply all Windows updates immediately (monitor MSRC for an emergency RedSun-specific patch . None released as of April 17, 2026 ). Supplement Defender with a secondary EDR solution (e.g., Huntress) capable of detecting Defender bypasses.

  2026-05-26 02:59 UTC
• Microsoft Patch Tuesday for May 2026 — Snort rules and prominent ...
  web:blog.talosintelligence.com

  Microsoft has released its monthly security update for May 2026 , which includes 137 vulnerabilities affecting a range of products, including 16 that Microsoft marked as "critical".

  2026-05-26 02:59 UTC
• April 2026 Critical Patch Update Released | security - Oracle Blogs
  web:blogs.oracle.com

  For more information about the Critical Patch Update program, see the security vulnerability remediation practices page located on the Oracle Trust Center.

  2026-05-26 02:59 UTC
• Zero-Day Threat Report May 2026 - CVEs, Exploits & Remediation ...
  web:carthageelectronics.com

  Status: Actively exploited — CISA KEV listed — patch by May 12, 2026 What Happened On April 28, 2026 , CISA added CVE - 2026 -32202 to its Known Exploited Vulnerabilities (KEV) catalog with a federal remediation deadline of May 12, 2026 . This vulnerability is the result of an incomplete patch Microsoft released in February for CVE - 2026 -21510.

  2026-05-26 02:59 UTC
• CISA Warns of Exploited Microsoft Defender 0-Day Flaws
  web:cyberpress.org

  The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added two actively exploited Microsoft Defender vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog, issuing an urgent remediation directive for federal agencies with a due date of June 3, 2026 .

  2026-05-26 02:59 UTC
• Patch Tuesday, April 2026 Edition - Krebs on Security
  web:krebsonsecurity.com

  For a clickable, per- patch breakdown, check out the SANS Internet Storm Center Patch Tuesday roundup. Running into problems applying any of these updates?

  2026-05-26 02:59 UTC
• Security Update Guide - Microsoft
  web:msrc.microsoft.com

  The Microsoft Security Response Center (MSRC) investigates all reports of security vulnerabilities affecting Microsoft products and services, and provides the information here as part of the ongoing effort to help you manage security risks and help keep your systems protected.

  2026-05-26 02:59 UTC
• CISA orders feds to patch BlueHammer flaw exploited as zero-day
  web:www.bleepingcomputer.com

  CISA has ordered U.S. federal agencies to patch a Microsoft Defender privilege escalation flaw (dubbed BlueHammer) that has been exploited in zero-day attacks.

  2026-05-26 02:59 UTC
• April 2026 Patch Tuesday: Updates and Analysis | CrowdStrike
  web:www.crowdstrike.com

  Microsoft's April 2026 Patch Tuesday addresses 164 CVEs , featuring 8 Critical vulnerabilities, one exploited zero-day, and one disclosed zero-day.

  2026-05-26 02:59 UTC
• Microsoft Issues Massive Windows Patch for 160+ Bugs ... - TechRepublic
  web:www.techrepublic.com

  Microsoft's April 2026 Patch Tuesday fixes 165 vulnerabilities, including two zero-days, in one of the company's largest monthly security updates.

  2026-05-26 02:59 UTC

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