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URL Redirection to Untrusted Site ('Open Redirect') in koa

CVE-2025-62595

  • koa
  • org.webjars.npm:koa
Medium
6.1/10

Summary

Koa is expressive middleware for Node.js using ES2017 async functions. 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 affects versions prior to 2.16.3 and 3.0.x prior to 3.0.3.

  • LOW
  • NETWORK
  • LOW
  • CHANGED
  • REQUIRED
  • NONE
  • LOW
  • NONE

CWE-601 - Open Redirect

An open redirect attack employs a URL parameter, HTML refresh tags, or a DOM based location change to exploit the trust of a vulnerable domain to direct the users to a malicious website. The attack could lead to higher severity vulnerabilities such as unauthorized access control, account takeover, XSS, and more.

References

Advisory Timeline

  • Published