Vulnerability in Nextcloud Server
CVE-2021-32679
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`.
EPSS: 0.014 (69.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 3.5 (Low). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N.
Affected products
- Nextcloud Nextcloud_server
- Nextcloud Security-advisories — versions < 19.0.13, >= 20.0.0, < 20.0.11, >= 21.0.0, < 21.0.3
- Fedoraproject Fedora — versions 33, 34
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Third Party Advisory)
- security-advisories@github.com (Patch, Third Party Advisory, x_refsource_MISC)
- security-advisories@github.com (Permissions Required, x_refsource_MISC)
- security-advisories@github.com (x_refsource_FEDORA, vendor-advisory)
- security-advisories@github.com (x_refsource_FEDORA, vendor-advisory)
- security-advisories@github.com (vendor-advisory, Third Party Advisory, x_refsource_GENTOO)
Frequently asked questions
- What is CVE-2021-32679?
- CVE-2021-32679 is a low-severity vulnerability in Nextcloud Server, classified under Improper Encoding or Escaping of Output. CVSS score: 3.5/10. Published 2021-07-12.
- How severe is CVE-2021-32679?
- Low severity. CVSS v3 base score is 3.5 out of 10.