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VulnerabilityPublished

CVE-2026-33491: zenc · Stack-based Buffer Overflow

Affects zencSource CVE Database V5

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Not known to be exploited · CVSS 7.8 High : upgrade to 0.4.4 soon.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 15% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 0.4.4
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 26 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade zenc and zenc-lang/zenc to 0.4.4.

Affected software

ProductAffectedFixed in
zenc-langzencAffected
  • <0.4.4
Fixed in
  • 0.4.4
GitHubzenc-lang/zencpkg:github/zenc-lang/zencOther threatsAffected
  • <0.4.4
Fixed in
  • 0.4.4

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate this vulnerability, organizations should immediately upgrade all instances of the Zen C compiler to version 0.4.4 or later, where the buffer overflow has been fixed. Restrict access to the compiler to trusted users only, and monitor usage to detect any anomalous or unauthorized compilation activities. Implement strict input validation and code review policies for Zen C source files, especially those containing unusually long identifiers. Employ runtime protections such as stack canaries, address space layout randomization (ASLR), and control flow integrity (CFI) in the build environment to reduce exploitation risk. Consider sandboxing the compiler process to limit the impact of potential exploitation. Regularly audit and update development tools and dependencies to ensure vulnerabilities are promptly addressed. Finally, educate developers and system administrators about the risks of processing untrusted source code.

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 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.

References

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