link-preview-js vulnerable to IPv6 and internal loopback attacks

### Impact The library did not check for IPv6 loopback attacks. There was also a DNS attack, where an address could be resolved into an internal IP. This could cause internal data leaks. ### Patches Problem has been patched in version 4.0.1. However, it cannot be completely solved by the package alone. The regex used for validation has been tightened for IPv6 addresses. The DNS resolving, however, is more difficult. The regex has been tightened to prohibit .internal, .local, .nip.io and .sslip.io addresses, however there can be other services not on the list, therefore it is imperative that users use the resolveDNSHost option to do DNS resolution before fetching content. To that regard a (scary) error message has been added when the option is not set. ### Workarounds Users can do their own validation before fetching content. Reported by https://github.com/Andrew-most-likely

Source published

5 May 2026 20:13:02 UTC

Source modified

13 May 2026 14:35:04 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Publisher rating · HIGH