CVE-2025-15104

Nu Html Checker (validator.nu) - Restriction bypass vulnerability allowing local SSRF

Published Jan 16, 2026 CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed
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

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-fccg-7w3p-w66f Nu Html Checker (vnu) contains a Server-Side Request Forgery (SSRF) vulnerability
History
Type Values Removed Values Added
First Time appeared Validator
Validator validator
CPEs cpe:2.3:a:validator:validator:*:*:*:*:*:*:*:*
Vendors & Products Validator
Validator validator
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N'}

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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).
Title Nu Html Checker (validator.nu) - Restriction bypass vulnerability allowing local SSRF
First Time appeared The Nu Html Checker
The Nu Html Checker the Nu Html Checker
Weaknesses CWE-918
CPEs cpe:2.3:a:the_nu_html_checker:the_nu_html_checker:latest_-_commit_23f090a11bab8d0d4e698f1ffc197a4fe226a9cd:*:linux:*:*:*:*:*
cpe:2.3:a:the_nu_html_checker:the_nu_html_checker:latest_-_commit_23f090a11bab8d0d4e698f1ffc197a4fe226a9cd:*:macos:*:*:*:*:*
cpe:2.3:a:the_nu_html_checker:the_nu_html_checker:latest_-_commit_23f090a11bab8d0d4e698f1ffc197a4fe226a9cd:*:windows:*:*:*:*:*
Vendors & Products The Nu Html Checker
The Nu Html Checker the Nu Html Checker
References
Metrics cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Fluid Attacks
Published
Updated
Jan 16, 2026, 2:30 PM
Reserved
Dec 26, 2025, 1:34 PM
Status
Analyzed
Published
Jan 16, 2026, 2:15 PM
Modified
Jun 17, 2026, 8:37 AM