CVE-2026-33491
Published: 26 March 2026
Summary
CVE-2026-33491 is a high-severity Stack-based Buffer Overflow (CWE-121) vulnerability in Zenc-Lang Zen C. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked at the 5.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-16 (Memory Protection) and SI-2 (Flaw Remediation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly requires timely remediation of the stack-based buffer overflow flaw in the Zen C compiler by patching to version 0.4.4 or later.
Implements memory protections such as stack canaries, ASLR, or DEP to prevent arbitrary code execution from exploitation of the stack-based buffer overflow.
Requires validation of information inputs like excessively long identifiers in Zen C source files to block the trigger for the buffer overflow vulnerability.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Buffer overflow in Zen C compiler enables RCE when victim compiles attacker-crafted .zc source file (user interaction, no privileges needed); directly maps to exploitation of client software for execution and delivery via malicious file.
NVD Description
Zen C is a systems programming language that compiles to human-readable GNU C/C11. Prior to version 0.4.4, a stack-based buffer overflow vulnerability in the Zen C compiler allows attackers to cause a compiler crash or potentially execute arbitrary code by…
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providing a specially crafted Zen C source file (`.zc`) with excessively long struct, function, or trait identifiers. Users are advised to update to Zen C version v0.4.4 or later to receive a patch.
Deeper analysisAI
CVE-2026-33491 is a stack-based buffer overflow vulnerability (CWE-121, CWE-787) in the Zen C compiler, a systems programming language that compiles to human-readable GNU C/C11. The issue affects versions prior to 0.4.4 and is triggered by processing a specially crafted Zen C source file (.zc) containing excessively long struct, function, or trait identifiers. It has a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H), indicating high impact on confidentiality, integrity, and availability.
An attacker with local access to a system running the vulnerable Zen C compiler can exploit this by tricking a user into compiling a malicious .zc file, which requires user interaction but no special privileges. Successful exploitation can cause the compiler to crash or, in some cases, allow arbitrary code execution on the host machine where the compilation occurs.
The GitHub security advisory at https://github.com/zenc-lang/zenc/security/advisories/GHSA-rv74-w6q7-h8xr recommends updating to Zen C version v0.4.4 or later, which includes a patch to address the buffer overflow.
Details
- CWE(s)