CVE-2021-32802

moderate-risk
Published 2021-09-07

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 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`.

Do I need to act?

~
2.3% chance of exploitation in next 30 days
EPSS score — moderate exploit probability
-
Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
9
CVSS 9.3/10 Critical
NETWORK / LOW complexity

Affected Products (1)

Affected Vendors

Nextcloud

References (8)

Vendor Advisory https://docs.nextcloud.com/server/21/admin_manual/configuration_files/previews_c...
Mitigation https://github.com/nextcloud/security-advisories/security/advisories/GHSA-m682-v...
Permissions Required https://hackerone.com/reports/1261413
Third Party Advisory https://security.gentoo.org/glsa/202208-17
Vendor Advisory https://docs.nextcloud.com/server/21/admin_manual/configuration_files/previews_c...
Mitigation https://github.com/nextcloud/security-advisories/security/advisories/GHSA-m682-v...
Permissions Required https://hackerone.com/reports/1261413
Third Party Advisory https://security.gentoo.org/glsa/202208-17
41
/ 100
moderate-risk
Severity 31/34 · Critical
Exploitability 5/34 · Minimal
Exposure 5/34 · Minimal