CVE-2021-32679

Description

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.13, 20.0.11, and 21.0.3, filenames where not escaped by default in controllers using `DownloadResponse`. When a user-supplied filename was passed unsanitized into a `DownloadResponse`, this could be used to trick users into downloading malicious files with a benign file extension. This would show in UI behaviours where Nextcloud applications would display a benign file extension (e.g. JPEG), but the file will actually be downloaded with an executable file extension. The vulnerability is patched in versions 19.0.13, 20.0.11, and 21.0.3. Administrators of Nextcloud instances do not have a workaround available, but developers of Nextcloud apps may manually escape the file name before passing it into `DownloadResponse`.

CvssV3 impact

BaseSeverity

HIGH

ConfidentialityImpact

HIGH

AttackComplexity

LOW

Scope

UNCHANGED

AttackVector

NETWORK

AvailabilityImpact

HIGH

IntegrityImpact

HIGH

PrivilegesRequired

NONE

BaseScore

8.8

VectorString

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

Version

3.1

UserInteraction

REQUIRED

CvssV2 impact

AccessComplexity

MEDIUM

ConfidentialityImpact

PARTIAL

AvailabilityImpact

PARTIAL

IntegrityImpact

PARTIAL

BaseScore

6.8

VectorString

AV:N/AC:M/Au:N/C:P/I:P/A:P

Version

2.0

AccessVector

NETWORK

Authentication

NONE