AZL-113468: CVE-2026-97035 affecting package golang 1.27.4-1
When using Clang or GCC, building a malicious package that uses cgo could cause unexpected code execution at build time or write files to arbitrary directories via "-gen-" or "-gnat" flags in "#cgo" directives. The "-g" wildcard in the compiler and linker flag allowlists previously matched Clang's two-argument "-gen-cdb-fragment-path <dir>" flag and GCC's two-argument "-gnatO <file>" flag, permitting compilation database fragments and sidecar output files to be written to arbitrary directories and desynchronizing flag argument parsing between the go command and the compiler driver so that subsequent arguments could be passed as unvalidated positional inputs to the linker. "-gen-" and "-gnat" flags are now disallowed in "#cgo" compiler and linker flags.
Affected Software
Event History
Frequently Asked Questions
Who is exposed to this issue?
Systems that build untrusted or malicious Go packages using cgo are exposed when the build uses Clang or GCC. The risk is at build time rather than limited to execution of the resulting program.
What does an attacker need to exploit it?
An attacker needs to supply a package containing cgo directives with the affected compiler or linker flags and have it built with the Go toolchain using Clang or GCC. The crafted flags can cause writes to arbitrary directories and may cause subsequent arguments to reach the linker as unvalidated positional inputs.
What changed to prevent exploitation?
The Go toolchain now disallows -gen-* and -gnat* flags in #cgo compiler and linker flags. These flags had previously matched the -g* allowlist wildcard despite taking a separate argument.