Vulnerability library
Security checkJanuary 16, 2026

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

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Medium severitynpmvnu-jar

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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.

Recommendation

No fix is available yet. Followings are affected versions:

  • <= 26.1.11

References

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See something that needs correcting? Let us knowUpdated January 16, 2026