What is the CVSS score of CVE-2025-15104?

CVE-2025-15104 has a CVSS 3.1 base score of 5.3 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N. EPSS exploitation probability: 0.0%.

Is there a public PoC exploit available for CVE-2025-15104?

Yes, a public proof-of-concept exploit is available for CVE-2025-15104. Prioritise patching immediately. EPSS: 0.0%.

How to fix or mitigate CVE-2025-15104?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Monitor vendor channels for patch availability.

Validator CVE-2025-15104

MEDIUM

Server-Side Request Forgery (SSRF) (CWE-918)

2026-01-16 help@fluidattacks.com

GHSA-fccg-7w3p-w66f

DNS Validator

5.3

CVSS 3.1 · NVD

View

Vulnerability Assessment

Weakness	CWE CWE-918 OWASP Top 10:2025 A01:2025 - Broken Access Control ASVS 5.0 V4 - API and Web Service URL allowlisting, SSRF prevention MITRE ATT&CK 2 techniques across 2 tactics: Initial Access, Credential Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS 5.3 (MEDIUM). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: None. Exploitable via remote/network. Public exploit/POC available.
Exploit ScenarioDerived	A remote attacker could exploit this vulnerability to make the server perform arbitrary HTTP/HTTPS requests to internal resources, inc.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

No patch listed yet 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

RemediationAI

Monitor vendor advisories for a patch. Restrict network access to the affected service where possible.

Affected Packages

maven nu.validator:validator no fix

maven vnu-jar no fix

npm nu.validator:validator no fix

npm vnu-jar no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 2 packages in maven, npm

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Classified as CWE-918 (Server-Side Request Forgery (SSRF)). Affects Validator. 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 23f090a11bab8d0d4e698f

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.3 MEDIUM

AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Lifecycle Timeline

PoC Detected

Jan 23, 2026 - 16:57 vuln.today

Public exploit code

CVE Published

Jan 16, 2026 - 14:15 nvd

MEDIUM 5.3

DescriptionCVE.org

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).

Executive ViewAI

Why It Matters

CVE-2025-15104 presents moderate security risk, a server-side request forgery vulnerability rated CVSS 5.3. Users could be tricked into performing unintended actions. Proof-of-concept code is publicly available. Organizations should apply vendor updates when available and monitor for exploitation.

Business Impact: Low

Compensating Controls

Apply vendor patch. If patching is delayed: implement egress filtering, block metadata endpoints.

Threat Intelligence Overview

EPSS Score

0.0%

Top 94% exploitable

Exploit

POC

Public exploit code exists

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS

GitHub

VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity MEDIUM

CISA KEV No

Public POC Yes

EPSS 0.0%

Patch available No

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.