CVE-2026-6366: Drupal/core Drupal Core Allows Object Injection Vulnerability

MODERATE
Advisory Identifier: GHSA-xmjc-63pr-2mpg
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CVSS 6.6
CWE-915
Published
Advisory Summary

CVE-2026-6366 is a MODERATE (CVSS 6.6) drupal core allows object injection vulnerability (CWE-915: Improperly Controlled Modification of Dynamically-Determined Object Attributes) affecting Drupal/core libraries in the Packagist ecosystem. The issue involves drupal core allows object injection. Remediation is available by upgrading affected packages to version 10.5.9, 10.6.7, 11.2.11, 11.3.7.

CVE-2026-6366 at a Glance

CVE Identifier CVE-2026-6366
GHSA Identifier GHSA-xmjc-63pr-2mpg
Severity MODERATE
CVSS v3.1 Base Score 6.6
CWE Classification CWE-915: Improperly Controlled Modification of Dynamically-Determined Object Attributes
Affected Product Drupal/core
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 6.6

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required High (PR:H)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-6366

To remediate this vulnerability, upgrade all affected Drupal/core dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

drupal/core fixed: 10.5.9 
Upgrade drupal/core to 10.5.9
drupal/core fixed: 10.6.7 
Upgrade drupal/core to 10.6.7
drupal/core fixed: 11.2.11 
Upgrade drupal/core to 11.2.11
drupal/core fixed: 11.3.7 
Upgrade drupal/core to 11.3.7
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for drupal/core

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-6366, inspect your project dependencies for Drupal/core:

inspect dependencies for drupal/core

Analyze the terminal output to locate any version of Drupal/core in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 10.5.9), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-915: Improperly Controlled Modification of Dynamically-Determined Object Attributes, where the product receives input from an upstream component that specifies multiple attributes, properties, or fields that are to be initialized or updated in an object, but it does not properly control which attributes can be modified. In Drupal/core, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Improperly Controlled Modification of Dynamically-Determined Object Attributes vulnerability in Drupal Drupal core allows Object Injection. This issue affects Drupal core: from 8.0.0 before 10.5.9, from 10.6.0 before 10.6.7, from 11.0.0 before 11.2.11, from 11.3.0 before 11.3.7.

CVE-2026-6366 Affected Drupal/core Versions

4 component(s)
Fixed Versions:
10.5.910.6.711.2.1111.3.7
Product / Package Ecosystem Affected Versions Fixed Version
drupal/core
 Packagist
≥ 8.0.0
< 10.5.9
10.5.9
drupal/core
 Packagist
≥ 10.6.0
< 10.6.7
10.6.7
drupal/core
 Packagist
≥ 11.0.0
< 11.2.11
11.2.11
drupal/core
 Packagist
≥ 11.3.0
< 11.3.7
11.3.7

References

NVD — CVE-2026-6366 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-6366
Drupal/core Source Repository REPOSITORY
https://github.com/drupal/core
www.drupal.org/sa-core-2026-002 WEB
https://www.drupal.org/sa-core-2026-002

Frequently Asked Questions

What is CVE-2026-6366?
CVE-2026-6366 is a security vulnerability in Drupal/core involving Drupal core allows Object Injection under CWE-915: Improperly Controlled Modification of Dynamically-Determined Object Attributes.
Which Drupal/core versions are affected?
Affected versions include releases prior to 10.5.9, 10.6.7, 11.2.11, 11.3.7 across affected packages: drupal/core.
What version fixes CVE-2026-6366?
Upgrading to 10.5.9, 10.6.7, 11.2.11, 11.3.7 (or the latest patched release for your respective branch) resolves the vulnerability.
Is drupal/core affected?
Yes, drupal/core is affected in releases prior to 10.5.9, 10.6.7, 11.2.11, 11.3.7. Upgrade your dependency to 10.5.9, 10.6.7, 11.2.11, 11.3.7 or later.
What is the CVSS score of CVE-2026-6366?
CVE-2026-6366 has a CVSS v3.1 base score of 6.6 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-6366?
CVE-2026-6366 is classified under CWE-915: Improperly Controlled Modification of Dynamically-Determined Object Attributes (The product receives input from an upstream component that specifies multiple attributes, properties, or fields that are to be initialized or updated in an object, but it does not properly control which attributes can be modified.).
How can I check Packagist dependencies for CVE-2026-6366?
Run the dependency tree command: 'inspect dependencies for drupal/core'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-xmjc-63pr-2mpg",
  "modified" : "2026-06-05T18:18:11Z",
  "published" : "2026-05-20T00:31:42Z",
  "aliases" : [ "CVE-2026-6366" ],
  "summary" : "Drupal core allows Object Injection",
  "details" : "Improperly Controlled Modification of Dynamically-Determined Object Attributes vulnerability in Drupal Drupal core allows Object Injection.\n\nThis issue affects Drupal core: from 8.0.0 before 10.5.9, from 10.6.0 before 10.6.7, from 11.0.0 before 11.2.11, from 11.3.0 before 11.3.7.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "drupal/core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "8.0.0"
      }, {
        "fixed" : "10.5.9"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "drupal/core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.6.0"
      }, {
        "fixed" : "10.6.7"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "drupal/core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "11.0.0"
      }, {
        "fixed" : "11.2.11"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "drupal/core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "11.3.0"
      }, {
        "fixed" : "11.3.7"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-6366"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/drupal/core"
  }, {
    "type" : "WEB",
    "url" : "https://www.drupal.org/sa-core-2026-002"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-915" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-05T18:18:11Z",
    "nvd_published_at" : "2026-05-19T23:16:58Z"
  }
}