CVE-2026-28207

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine without logging in, but needs a user to act. High risk of data tampering.

Exploit odds

1.1% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-02-26 23:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 10:28 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 1.1% in the next 30 days (EPSS).
• Severity: 6.6 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-02-26 23:16 UTC

Last modified

2026-06-17 10:28 UTC

Exploit probability

1.1% · EPSS, next 30 days

Weakness

CWE-78 · OS command injection

Record status

Analyzed

Affected

• zenc-lang Zen C < 0.4.2

Attack profile CVSS 3.1 · 6.6

Attack vector

Local

Complexity

Low

Privileges needed

None

User interaction

Required

Scope

Unchanged

Confidentiality

Low

Integrity

High

Availability

Low

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-28207.md and follow it. Check whether this project is affected by CVE-2026-28207. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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