CVE-2021-32802
Published: 07 September 2021
Summary
CVE-2021-32802 is a critical-severity Inclusion of Functionality from Untrusted Control Sphere (CWE-829) vulnerability in Nextcloud Nextcloud Server. Its CVSS base score is 9.3 (Critical).
Operationally, ranked in the top 15.0% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-19562
Vulnerability details
Nextcloud server is an open source, self hosted personal cloud. Nextcloud supports rendering image previews for user provided file content. For some image types, the Nextcloud server was invoking a third-party library that wasn't suited for untrusted user-supplied content. There…
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are several security concerns with passing user-generated content to this library, such as Server-Side-Request-Forgery, file disclosure or potentially executing code on the system. The risk depends on your system configuration and the installed library version. It is recommended that the Nextcloud Server is upgraded to 20.0.12, 21.0.4 or 22.1.0. These versions do not use this library anymore. As a workaround users may disable previews by setting `enable_previews` to `false` in `config.php`.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Limiting P2P file sharing technology reduces inclusion of functionality or resources from untrusted external control spheres.
Enforcing installation policies prevents users from including functionality obtained from untrusted control spheres.
The inventory process requires identifying and recording the origin of all components, making inclusion of functionality from untrusted control spheres easier to detect during reviews.
Requiring approval and monitoring of maintenance tools prevents inclusion and execution of functionality obtained from untrusted sources.
Unowned portable devices represent untrusted control spheres; the prohibition prevents inclusion of functionality or data from such sources.
Strategy mandates assessment of third-party components and suppliers, directly reducing inclusion of functionality from untrusted control spheres.
Procedures can mandate supply-chain vetting and restrictions on functionality obtained from untrusted third-party or external control spheres.
Requires use of trusted sources and provenance tracking, tangibly limiting inclusion of functionality from untrusted control spheres.