Nim is a statically typed compiled systems programming language. In Nim standard library before 1.4.2, httpClient SSL/TLS certificate verification was disabled by default. Users can upgrade to version 1.4.2 to receive a patch or, as a workaround, set "verifyMode = CVerifyPeer" as documented.
https://github.com/nim-lang/security/security/advisories/GHSA-9vqv-2jj9-7mqr