CVE-2021-32802

CRITICALNVD 9.39.3
EchelonGraph scoreLOW confidence

This critical-severity CVE scores 9.3 under NVD CVSS v3. EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: nvd
9.3
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 3%CVSS: 9.3Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.3
EG Score
9.3(low)
EPSS
83.7%
KEV
Not listed

Published

September 7, 2021

Last Modified

November 21, 2024

Advisory Details (4)

Auto-updated Jul 17, 2026
Patch available. Sources: github.
generic

Nextcloud: Multiple Vulnerabilities (GLSA 202208-17) — Gentoo security

https://security.gentoo.org/glsa/202208-17
generic

HackerOne

https://hackerone.com/reports/1261413
github Patch Available

Preview generation used third-party library not suited for user-generated content · Advisory · nextcloud/security-advisories · GitHub

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-m682-v4g9-wrq7
generic

Previews configuration — Nextcloud latest Administration Manual latest documentation

https://docs.nextcloud.com/server/21/admin_manual/configuration_files/previews_configuration.html#disabling-previews

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 45× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-22 14:06 UTCEPSS rescore
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  74. 2026-05-23 08:23 UTCEG score recompute

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Frequently asked(5)

What is CVE-2021-32802?
CVE-2021-32802 is a critical vulnerability published on September 7, 2021. 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…
When was CVE-2021-32802 disclosed?
CVE-2021-32802 was first published in the National Vulnerability Database on September 7, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-32802 actively exploited?
CVE-2021-32802 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 83.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-32802?
CVE-2021-32802 has a CVSS v3 base score of 9.3 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2021-32802?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-32802, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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