CVE-2026-28207
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.94%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 7.3 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
- EPSS
- 0.94% probability · 59th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-78
- Affected
- zenc-lang/zen c
- Source
- security-advisories@github.com
References
- 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
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.