CVE-2025-62595

Medium

Description

Koa is expressive middleware for Node.js using ES2017 async functions. In versions 2.16.2 to before 2.16.3 and 3.0.1 to before 3.0.3, a bypass to CVE-2025-8129 was discovered in the Koa.js framework affecting its back redirect functionality. In certain circumstances, an attacker can manipulate the Referer header to force a user’s browser to navigate to an external, potentially malicious website. This occurs because the implementation incorrectly treats some specially crafted URLs as safe relative paths. Exploiting this vulnerability could allow attackers to perform phishing, social engineering, or other redirect-based attacks on users of affected applications. This issue has been patched in version 3.0.3.

SeverityMedium
CVSS4.3
Exploit probability—
ProductKoa
PublishedOct 21, 2025
First seenOct 21, 2025

How to fix

Update
  • koajs koa3.0.3 or later
  • koa3.0.3, 2.16.3 or later

Affected products

ProductAffected versionsFixed in
koajs koa3.0.1 ≤ v < 3.0.3, 2.16.23.0.3
koanpm3.0.1 ≤ v < 3.0.3, 2.16.2 ≤ v < 2.16.33.0.3, 2.16.3

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