Arbitrary file write using cgo pkg-config directive in cmd/go

Vulnerability Description

Building a malicious file with cmd/go can cause can cause a write to an attacker-controlled file with partial control of the file content. The "#cgo pkg-config:" directive in a Go source file provides command-line arguments to provide to the Go pkg-config command. An attacker can provide a "--log-file" argument to this directive, causing pkg-config to write to an attacker-controlled location.

References

• https://go.dev/cl/736711
• https://go.dev/issue/77100
• https://groups.google.com/g/golang-announce/c/Vd2tYVM8eUc
• https://pkg.go.dev/vuln/GO-2026-4339