CVE-2021-21355

Unrestricted Upload of File with Dangerous Type in packagist/typo3/cms-core

Identifier

CVE-2021-21355

Package Slug

packagist/typo3/cms-core

Vulnerability

Unrestricted Upload of File with Dangerous Type

Description

Due to the lack of ensuring file extensions belong to configured allowed mime-types, attackers can upload arbitrary data with arbitrary file extensions - however, default _fileDenyPattern_ successfully blocked files like _.htaccess_ or _malicious.php_. Additionally, _UploadedFileReferenceConverter_ transforming uploaded files into proper FileReference domain model objects handles possible file uploads for other extensions as well - given those extensions use the Extbase MVC framework, make use of FileReference items in their direct or inherited domain model definitions and did not implement their own type converter. In case this scenario applies, _UploadedFileReferenceConverter_ accepts any file mime-type and persists files in the default location. In any way, uploaded files are placed in the default location _/fileadmin/user_upload/_, in most scenarios keeping the submitted filename - which allows attackers to directly reference files, or even correctly guess filenames used by other individuals, disclosing this information. No authentication is required to exploit this vulnerability.

Affected Versions

All versions starting from 8.0.0 before 8.7.40, all versions starting from 9.0.0 before 9.5.25, all versions starting from 10.0.0 before 10.4.14, all versions starting from 11.0.0 before 11.1.1

Solution

Upgrade to versions 8.7.40, 9.5.25, 10.4.14, 11.1.1 or above.

Last Modified

2021-03-29

source