The "go tool pack" subcommand (usually used only by the compiler as an internal tool with known-good inputs) does not sanitize output filenames. Extracting a malicious archive file with the "pack" subcommand can write files to arbitrary locations on the filesystem.
Exploitability
AV:LAC:LPR:LUI:RScope
S:CImpact
C:NI:HA:N5.9/CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:N