CVE-2025-15104

5.3 MEDIUM
Published: January 16, 2026 Modified: January 23, 2026
View on NVD

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).

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://fluidattacks.com/advisories/europe
Source: help@fluidattacks.com
Exploit Third Party Advisory
https://github.com/validator/validator
Source: help@fluidattacks.com
Product
https://fluidattacks.com/advisories/europe
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Exploit Third Party Advisory

3 reference(s) from NVD

Quick Stats

CVSS v3 Score
5.3 / 10.0
EPSS (Exploit Probability)
0.0%
7th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

validator