Hex package manager version 0.14.0 through 0.18.2 contains a Signing oracle vulnerability in Package registry verification that can result in Package modifications not detected, allowing code execution. This attack appears to be exploitable via victim fetches packages from malicious/compromised mirror. This vulnerability appears to have been fixed in 0.19.

References

• https://nvd.nist.gov/vuln/detail/CVE-2019-1000012
• hexpm/hex#646
• hexpm/hex#651