UBUNTU-CVE-2026-97035: Medium severity ubuntu/golang-1.10 vulnerability
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 with Clang or GCC are exposed. The affected Ubuntu package set includes golang-1.6, golang-1.8, golang-1.10, golang-1.13, golang-1.16, golang-1.18, golang-1.22, and golang-1.24.
What does an attacker need to exploit it?
An attacker needs to supply a package that is built with cgo and contains crafted #cgo compiler or linker directives. Exploitation depends on the build using Clang or GCC and processing the previously allowed -gen-* or -gnat* flags.
What can happen during exploitation?
A malicious package can cause unexpected code execution during its build. It can also write compilation database fragments or sidecar output files to arbitrary directories, and may cause later arguments to reach the linker as unvalidated positional inputs.
What is the relevant mitigation if updates cannot be applied immediately?
Do not build untrusted cgo-enabled packages with Clang or GCC. In particular, reject or review #cgo compiler and linker directives using -gen-* or -gnat* flags.