How severe is CVE-2020-13666?

CVE-2020-13666 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2020-13666?

CVE-2020-13666 affects the following packages: drupal/core (Packagist), drupal/core (Packagist), drupal/core (Packagist), drupal/core (Packagist), drupal/drupal (Packagist), drupal/drupal (Packagist), drupal/drupal (Packagist), drupal/drupal (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2020-13666?

Update drupal/core to 8.8.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-13666 is resolved across your whole dependency graph.

How do I detect CVE-2020-13666 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for drupal/core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2020-13666 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2020-13666 actively exploited in the wild?

No public exploit code has been indexed for CVE-2020-13666 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2020-13666?

CVE-2020-13666 has an EPSS (Exploit Prediction Scoring System) score of 2.9%, placing it in the 87th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2020-13666?

CVE-2020-13666 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2020-13666 published, and has it been updated?

CVE-2020-13666 was published on May 5, 2021 and was last updated on October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘

🐘 Packagist

Not in CISA KEV

MEDIUM severity

CVE-2020-13666 — core

MEDIUM

CVE-2020-13666 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in drupal/core. A fix is available for drupal/core — see the affected versions and patch details below.

Drupal Core Cross-site scripting vulnerability

Also known asBIT-drupal-2020-13666DRUPAL-CORE-2020-007GHSA-8jj2-x2gc-ggm7

Published

May 5, 2021

Updated

Oct 24, 2026

Affected

8 pkgs

Patched

8 / 8

Exploits

None indexed

Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

2.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs87th percentile — riskier than 87% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

8 pkgs affected

🐘drupal/core🐘drupal/core🐘drupal/core🐘drupal/core🐘drupal/drupal🐘drupal/drupal🐘drupal/drupal🐘drupal/drupal

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Cross-site scripting vulnerability in Drupal Core. Drupal AJAX API does not disable JSONP by default, allowing for an XSS attack. This issue affects: Drupal Drupal Core 7.x versions prior to 7.73; 8.8.x versions prior to 8.8.10; 8.9.x versions prior to 8.9.6; 9.0.x versions prior to 9.0.6.

Affected Packages

8 total 8 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`drupal/core`	≥ 8.8.0&&< 8.8.10	8.8.10`composer require drupal/core:^8.8.10`
🐘Packagist	`drupal/core`	≥ 8.9.0&&< 8.9.6	8.9.6`composer require drupal/core:^8.9.6`
🐘Packagist	`drupal/core`	≥ 9.0.0&&< 9.0.6	9.0.6`composer require drupal/core:^9.0.6`
🐘Packagist	`drupal/core`	≥ 7.0.0&&< 7.73	7.73`composer require drupal/core:^7.73`
🐘Packagist	`drupal/drupal`	≥ 7.0.0&&< 7.73	7.73`composer require drupal/drupal:^7.73`
🐘Packagist	`drupal/drupal`	≥ 8.8.0&&< 8.8.10	8.8.10`composer require drupal/drupal:^8.8.10`

Affected Products

1 product · 4 configurations

Application

drupaldrupal

≥ 9.0.0 && < 9.0.6

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for drupal/core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update drupal/core to 8.8.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-13666 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2020-13666 in your dependencies?

Find it across Packagist, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

6.1/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CWE Classification

CWE-79Cross-site Scripting (XSS)

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

OpenSSF Scorecard

Package health score

security-advisories

4.8/10

Maintained10/10

Code-Review10/10

Branch-Protection0/10

Assessed Nov 2, 2026

Timeline

Disclosed

May 5, 2021

Last updated

Oct 24, 2026

Identifiers

CVE-2020-13666

GHSA-8jj2-x2gc-ggm7

BIT-drupal-2020-13666

DRUPAL-CORE-2020-007

References

Advisorydrupal.org · sa core 2020 007 Advisorynvd.nist.gov · CVE 2020 13666 Webgithub.com · CVE 2020 13666.yaml Webgithub.com · CVE 2020 13666.yaml Packagegithub.com · core

Related vulnerabilities

This CVE is medium severity; 5 of 8 other CVEs affecting drupal/core are rated as high or higher (top: critical).

CVE-2026-6365CVE-2026-9082CVE-2026-6367CVE-2026-6366CVE-2025-13080CVE-2025-13082CVE-2025-13081CVE-2025-13083

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 24, 2026