CVE-2025-15104
5.3 · MEDIUMOverview
CVE-2025-15104 is a medium-severity vulnerability affecting validator validator. It was published on January 16, 2026 and has a CVSS 3.1 base score of 5.3 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
Nu Html Checker (validator.nu) contains a restriction bypass that allows remote attackers to make the server perform arbitrary HTTP/HTTPS requests to internal resources, including localhost services. While the validator implements hostname-based protections to block direct access to localhost and 127.0.0.1, these controls can be bypassed using DNS rebinding techniques or domains that resolve to loopback addresses.This issue affects The Nu Html Checker (vnu): latest (commit 23f090a11bab8d0d4e698f1ffc197a4fe226a9cd).
Remediation
Check the references section for vendor advisories and patches from validator. Update validator 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 |
|---|---|---|---|
| validator | validator | >= 0, < 2026-01-11 | Affected |
Frequently Asked Questions
What is CVE-2025-15104?
CVE-2025-15104 is a medium-severity vulnerability affecting validator validator. It was published on January 16, 2026 and has a CVSS 3.1 base score of 5.3 (MEDIUM).
How severe is CVE-2025-15104?
This vulnerability has a CVSS 3.1 base score of 5.3, 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-2025-15104?
Check the references section for vendor advisories and patches from validator. Update validator 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-2025-15104?
CyberStrike's AI-powered security agents can automatically detect CVE-2025-15104 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
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