CVE-2021-32802 Preview generation used third-party library not suited for user-generated content in Nextcloud server

2021-09-0721:45:11

CWE-829

GitHub_M

www.cve.org

nextcloud

cve-2021-32802

preview generation

third-party library

user-generated content

security concerns

server-side-request-forgery

file disclosure

code execution

upgrade

workaround

CVSS3

9.3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

NONE

Availability Impact

LOW

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

AI Score

9.5

Confidence

High

EPSS

0.003

Percentile

68.5%

JSON

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.

CNA Affected

[
  {
    "product": "security-advisories",
    "vendor": "nextcloud",
    "versions": [
      {
        "status": "affected",
        "version": "< 20.0.12"
      },
      {
        "status": "affected",
        "version": ">= 21.0.0, < 21.0.4"
      },
      {
        "status": "affected",
        "version": ">= 22.0.0, < 22.1.0"
      }
    ]
  }
]