CVE-2017-6920 Drupal PECL YAML parser unsafe object handling

What is CVE-2017-6920?

CVE-2017-6920 is a critical unsafe deserialization vulnerability in Drupal Drupal, published on 6 Aug 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-19

Which versions are affected by CVE-2017-6920?

4 open source packages ship an affected version, including drupal/core and drupal/drupal. It affects 1 product.

Products include Drupal Drupal.

How do I fix CVE-2017-6920?

Upgrade drupal/core to 8.3.4 or later.

Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.

Is CVE-2017-6920 being exploited?

There is no known exploitation of CVE-2017-6920 in the wild and no public exploit code.

Other vulnerabilities in Drupal Drupal

• CVE-2026-9082 Drupal Core SQL Injection Exploited Critical 9.8
• CVE-2020-13671 Drupal core Un-restricted Upload of File Exploited High 8.8
• CVE-2019-6340 Drupal Core Remote Code Execution Exploited High 8.1
• CVE-2009-3352 Other in n/a Critical 10.0
• CVE-2024-55636 Drupal core - Less critical - Gadget chain - SA-CORE-2024-006 Critical 9.8

All Drupal Drupal vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-9c24-g32g-35rj.