Vulnerability Monitor

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CVE-2021-32802

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`.

Security Impact Summary

This vulnerability carries a CRITICAL severity rating with a CVSS v3.1 score of 9.3, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts confidentiality (data exposure), and limited availability for affected systems. Impacting 1 product from nextcloud organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2021, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.

Published

2021-09-07T22:15:08.563

Last Modified

2024-11-21T06:07:46.450

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 9.3 (CRITICAL)

CVSSv2 Vector

AV:N/AC:L/Au:N/C:C/I:C/A:C

Access Vector: NETWORK
Access Complexity: LOW
Authentication: NONE
Confidentiality Impact: COMPLETE
Integrity Impact: COMPLETE
Availability Impact: COMPLETE

Exploitability Score

10.0

Impact Score

10.0

Weaknesses

Type: Secondary
CWE-829
Type: Primary
CWE-829

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	nextcloud	nextcloud_server	< 20.0.12	Yes
Application	nextcloud	nextcloud_server	< 21.0.4	Yes
Application	nextcloud	nextcloud_server	< 22.1.0	Yes

References

https://docs.nextcloud.com/server/21/admin_manual/configuration_files/previews_configuration.html#disabling-previews Vendor Advisory ([email protected])
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-m682-v4g9-wrq7 Mitigation, Third Party Advisory ([email protected])
https://hackerone.com/reports/1261413 Permissions Required, Third Party Advisory ([email protected])
https://security.gentoo.org/glsa/202208-17 Third Party Advisory ([email protected])
https://docs.nextcloud.com/server/21/admin_manual/configuration_files/previews_configuration.html#disabling-previews Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-m682-v4g9-wrq7 Mitigation, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://hackerone.com/reports/1261413 Permissions Required, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://security.gentoo.org/glsa/202208-17 Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For nextcloud's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.