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🛡️ CVE-2025-15104 — validator

🟡 CVSS 5.3 — Medium ✅ No Known Exploit CWE-918 NVD
5.3
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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

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).

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity none, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: Low — limited, and the attacker does not choose what is affected.
  • Integrity impact: None.
  • Availability impact: None.

Weakness class

CVE-2025-15104 is classified as CWE-918: Server-Side Request Forgery (SSRF). The server fetches a URL supplied by the caller, which can be pointed at internal systems it alone can reach.

Affected software

CVE-2025-15104 is recorded against 3 packages.

  • nu.validator:validator
  • validator (fixed in 2026-01-11)
  • vnu-jar

Timeline and source

Published on 16 January 2026 and last revised on 3 February 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

nvd.nist.gov (Advisory)
fluidattacks.com (Web)
github.com (Package)

Same weakness in other software

These advisories are the same class of weakness (CWE-918: Server-Side Request Forgery (SSRF)) in other software:

CVE-2025-15104 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Medium
CVSS Score 5.3
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CWE CWE-918
Public Exploit ✅ No
Source NVD
Published 2026-01-16
Updated 2026-08-20
Modified 2026-02-03
Fix URL N/A

Affected Packages

Software From version Fixed in
nu.validator:validator — —
validator — 2026-01-11
vnu-jar — —

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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