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CVE-2021-32679

Filenames not escaped by default in controllers using DownloadResponse

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 19.0.13, 20.0.11, 21.0.3
None on Exploit-DB, Metasploit or GitHub

Summary

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`.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • nextcloud security-advisories

    fixed in 19.0.13; From 20.0.0 · fixed in 20.0.11; From 21.0.0 · fixed in 21.0.3

References 6

GitHub · nextcloud/security-advisories

GitHub · nextcloud/server

hackerone.com

lists.fedoraproject.org

security.gentoo.org