Nu Html Checker (vnu) contains a Server-Side Request Forgery (SSRF) vulnerability

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

5.5 · 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/E:P · score source

EPSS

• CVE-2025-15104: 0.46% estimated exploitation activity in the next 30 days; percentile 40.34 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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).

Published by the source

16 Jan 2026, 15:31 UTC

Last modified by the source

3 Feb 2026, 03:17 UTC

Source last checked

26 Oct 2026, 12:41 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-fccg-7w3p-w66f

2. Revision 2 · amended · 24 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-fccg-7w3p-w66f

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# Patch Next advisory brief: CVE-2025-15104

Advisory: Nu Html Checker (vnu) contains a Server-Side Request Forgery (SSRF) vulnerability
IDs: CVE-2025-15104, GHSA-fccg-7w3p-w66f
Record: https://patchnext.com/advisories/cve-2025-15104 (revision 3, source checked 26 Oct 2026, 12:41 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven nu.validator:validator: affected <= 26.1.11
- npm vnu-jar: affected <= 26.1.11

## Suggested inspection (read-only)
- Maven nu.validator:validator: check the installed version with your package manager.
- `npm ls vnu-jar --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on nu.validator:validator, vnu-jar.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-fccg-7w3p-w66f (OSV record GHSA-fccg-7w3p-w66f lists affected ranges: Maven nu.validator:validator >=0 =0 <=26.1.11)
- Verified: https://github.com/advisories/GHSA-fccg-7w3p-w66f (GitHub-reviewed advisory GHSA-fccg-7w3p-w66f lists affected ranges: Maven nu.validator:validator >=0 =0 <=26.1.11)

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