How severe is CVE-2021-32802?

CVE-2021-32802 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability low.

Is CVE-2021-32802 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (84th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-32802?

CVE-2021-32802 affects Nextcloud Nextcloud Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-32802?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-32802 published?

CVE-2021-32802 was published on 2021-09-07 and last updated on 2026-06-17.

CVE-2021-32802

CVE-2021-32802 is a critical-severity vulnerability in Nextcloud Nextcloud Server with a CVSS 3.x base score of 9.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-829.

Key facts

Severity: Critical (CVSS 3.x base score 9.3)
CVSS v2: 10.0
EPSS exploit prediction: 3% (84th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-829
Affected product: Nextcloud Nextcloud Server
Published: 2021-09-07
Last modified: 2026-06-17

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`.

Frequently asked questions

What is 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`.
How severe is CVE-2021-32802?: CVE-2021-32802 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability low.
Is CVE-2021-32802 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (84th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-32802?: CVE-2021-32802 affects Nextcloud Nextcloud Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-32802?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-32802 published?: CVE-2021-32802 was published on 2021-09-07 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:*

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