Link Preview JS extracts web links information. Prior to 4.0.1, 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. This vulnerability is fixed in 4.0.1.
Exploitability
AV:NAC:LAT:NPR:NUI:NVulnerable System
VC:HVI:NVA:NSubsequent System
SC:NSI:NSA:N8.7/CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:NInput Validation