Zen CApplication · Zenc Lang

CVE-2026-28207

HIGH · 7.3 CVSS v3.1 Published 2026-02-26
Fix available
A fix is available. Upgrade to 0.4.2 or later.
See remediation →
73/100
Remediation priority · Elevated
Public exploit

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-78

User input reaches a shell or system command without being fully separated from the command itself, so an attacker can append their own instructions. Because these run with the application's privileges, it often means full control of the host. The lasting fix is to avoid the shell entirely — call APIs directly and pass arguments as data, never as concatenated strings.

General guidance for the os command injection class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Zen CApplication
Affected:< 0.4.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 0.4.2 or later
Fixed in 0.4.2
Recommended fix High confidence

Zen C v0.4.2

  1. 1. Identify the current Zen C compiler version by running `zc --version` or checking the installed package
  2. 2. Download Zen C version 0.4.2 or later from the official GitHub repository (github.com)
  3. 3. If using a package manager, update the package to version 0.4.2 or later
  4. 4. If building from source, clone the repository and check out version v0.4.2 or later tag
  5. 5. Rebuild and reinstall the compiler
  6. 6. Verify the new version is installed by running `zc --version`
  7. 7. Confirm the vulnerability is patched by testing that shell metacharacters in the `-o` argument are no longer executed

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-28207 in production — separate from our analysis above.

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