DRUPAL-CONTRIB-2026-279

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    DRUPAL-CONTRIB-2026-279

    Published: 28 Oct 2026Last Modified: 28 Oct 2026

    Summary:

    Details: S3 File System (s3fs) provides an additional file system to your Drupal site that stores files in Amazon's Simple Storage Service (S3) storage. The module doesn't sufficiently isolate upload context between separate object(file) operations in the same request resulting in the potential for objects to be uploaded with incorrect access control list (ACL) entries or corruption through incorrect operation metadata. This vulnerability is mitigated by the fact that an attacker must be able to trigger multiple file operations on S3FS. Some vectors are mitigated by: * Not enabling private:// takeover (`$settings['s3fs.use_s3_for_private'] = FALSE;`) or only enabled with `$settings['s3fs.upload_as_private'] = TRUE;` * The deployment does not utilize `hook_s3fs_stream_open_params_alter()`, `hook_s3fs_upload_params_alter()`, `hook_s3fs_copy_params_alter()`, or `hook_s3fs_command_params_alter()` If both points above have always been true, all currently known vectors are mitigated.

    References: https://www.drupal.org/sa-contrib-2026-279

    Affected packages

    Package

    Name: drupal/s3fs

    Purl: pkg:composer/drupal/s3fs?repository_url=https:%2F%2Fpackages.drupal.org%2F8

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -3.12.0

    Affected versions

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    DRUPAL-CONTRIB-2026-279 | CVE-DB