CVE-2026-28207

Zen C is a systems programming language that compiles to human-readable GNU C/C11. Prior to version 0.4.2, a command injection vulnerability (CWE-78) in the Zen C compiler allows local attackers to execute arbitrary shell commands by providing a specially crafted output filename via the `-o` command-line argument. The vulnerability existed in the `main` application logic (specifically in `src/main.c`), where the compiler constructed a shell command string to invoke the backend C compiler. This command string was built by concatenating various arguments, including the user-controlled output filename, and was subsequently executed using the `system()` function. Because `system()` invokes a shell to parse and execute the command, shell metacharacters within the output filename were interpreted by the shell, leading to arbitrary command execution. An attacker who can influence the command-line arguments passed to the `zc` compiler (like through a build script or a CI/CD pipeline configuration) can execute arbitrary commands with the privileges of the user running the compiler. The vulnerability has been fixed in version 0.4.2 by removing `system()` calls, implementing `ArgList`, and internal argument handling. Users are advised to update to Zen C version v0.4.2 or later.

• CWE-78

• https://github.com/z-libs/Zen-C/security/advisories/GHSA-9rff-x96h-76h2Exploit, Mitigation, Vendor Advisory
• https://f0nduesav0yarde.github.io/blog/vulnerabilities/cve-2026-28207/Exploit, Third Party Advisory
• https://github.com/z-libs/Zen-C/security/advisories/GHSA-9rff-x96h-76h2Exploit, Mitigation, Vendor Advisory

Published

Feb 26, 2026

Last Modified

Jun 17, 2026

Status

Analyzed