CVE-2021-32802

Name: CVE-2021-32802
Creator: NVD / NIST
Published: 2021-09-07T22:15:08.563+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 2.52%

Last modified Jun 17, 2026

CVE-2021-32802 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. Nextcloud server is an open source, self hosted personal cloud. Nextcloud supports rendering image previews for user provided file content. EPSS estimates a 2.52% chance of exploitation in the next 30 days.

Description

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`.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

2.52%

82.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Nextcloud	Nextcloud Server	< 20.0.12
Nextcloud	Nextcloud Server	>= 21.0.0, < 21.0.4
Nextcloud	Nextcloud Server	>= 22.0.0, < 22.1.0

References

https://docs.nextcloud.com/server/21/admin_manual/configuration_files/previews_configuration.html#disabling-previewsVendor Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-m682-v4g9-wrq7Mitigation, Third Party Advisory
https://hackerone.com/reports/1261413Permissions Required, Third Party Advisory
https://security.gentoo.org/glsa/202208-17Third Party Advisory
https://docs.nextcloud.com/server/21/admin_manual/configuration_files/previews_configuration.html#disabling-previewsVendor Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-m682-v4g9-wrq7Mitigation, Third Party Advisory
https://hackerone.com/reports/1261413Permissions Required, Third Party Advisory
https://security.gentoo.org/glsa/202208-17Third Party Advisory

Timeline

Published: Sep 7, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-32802?

How severe is CVE-2021-32802?

CVE-2021-32802 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 2.52% probability of exploitation in the next 30 days.

How do I fix CVE-2021-32802?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-32802?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST