Subject: [ASA-202102-7] nextcloud: directory traversal

Arch Linux Security Advisory ASA-202102-7
=========================================

Severity: Medium
Date    : 2021-02-06
CVE-ID  : CVE-2020-36193
Package : nextcloud
Type    : directory traversal
Remote  : Yes
Link    : https://security.archlinux.org/AVG-1464

Summary
=======

The package nextcloud before version 20.0.6-1 is vulnerable to
directory traversal.

Resolution
==========

Upgrade to 20.0.6-1.

# pacman -Syu "nextcloud>=20.0.6-1"

The problem has been fixed upstream in version 20.0.6.

Workaround
==========

None.

Description
===========

Tar.php in Archive_Tar through 1.4.11 allows write operations with
Directory Traversal due to inadequate checking of symbolic links, a
related issue to CVE-2020-28948.

Impact
======

A remote attacker might be able to write files in arbitrary file system
locations by uploading a crafted archive file that leads to directory
traversal.

References
==========

https://pear.php.net/bugs/bug.php?id=27008
https://github.com/pear/Archive_Tar/commit/cde460582ff389404b5b3ccb59374e9b389de916
https://github.com/nextcloud/3rdparty/commit/87062377878054f58d62f6b1853ed61664404de6
https://github.com/nextcloud/3rdparty/commit/4f95d388e0888c130316c2a21f160d553219ea48
https://security.archlinux.org/CVE-2020-36193