How severe is CVE-2017-6920?

CVE-2017-6920 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2017-6920 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 20% (97th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-6920?

CVE-2017-6920 affects Drupal. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2017-6920?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2017-6920 published?

CVE-2017-6920 was published on 2018-08-06 and last updated on 2026-06-17.

CVE-2017-6920

CVE-2017-6920 is a critical-severity vulnerability in Drupal with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 20% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-19.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 20% (97th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-19
Affected product: Drupal
Published: 2018-08-06
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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 safely during certain operations.
How severe is CVE-2017-6920?: CVE-2017-6920 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2017-6920 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 20% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-6920?: CVE-2017-6920 affects Drupal. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2017-6920?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2017-6920 published?: CVE-2017-6920 was published on 2018-08-06 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:drupal:drupal:*:*:*:*:*:*:*:*

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