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.
CVE-2021-32802
“—” beside the score: it is equal to NVD's CVSS score.
This critical-severity CVE scores 9.3 under NVD CVSS v3. EPSS exploit probability: 2.6% (85th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
- High severity, but no confirmed exploitation yet
No fix has been recorded since the CVE record was published in 2021 — use a compensating control (WAF / firewall / segmentation) and check the vendor's advisory.
- CVSS v3
- 9.3
- EG Score
- 9.3CRITICALmedium confidence
- EG Risk
- 43EG Risk 43/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity93% × 45%Impact severity (EG Severity): CVSS 9.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation2.6% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability0% × 15%CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: No fix has been recorded since the CVE record was published in 2021. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and check the vendor's advisory for a fix. - EPSS PROB
- 2.6%
- EPSS %ILE
- 85th
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (9.3): severity, escalated by confirmed exploitation. This CVE's 9.3 is its impact severity (EG Severity), not escalated.
- EG Severity
- 9.3 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
- EG Likelihood
- 2.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-22). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
No fix has been recorded since the CVE record was published in 2021. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and check the vendor's advisory for a fix.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
September 7, 2021
Last Modified
November 21, 2024
Advisory Details (4)
Auto-updated Sep 15, 2026Nextcloud: Multiple Vulnerabilities (GLSA 202208-17) — Gentoo security
https://security.gentoo.org/glsa/202208-17Preview 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-wrq7Previews configuration — Nextcloud latest Administration Manual latest documentation
https://docs.nextcloud.com/server/21/admin_manual/configuration_files/previews_configuration.html#disabling-previewsWeakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 14× in last 7d / 42× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
Showing the most recent 94 of 207 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 6 repeat rows among the latest 100 are merged into the row they repeat. The 113 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-10-23 16:28 UTCEPSS rescoreEPSS 2.6% · 85th percentile
- 2026-10-23 02:45 UTCEG score recompute
- 2026-10-22 16:29 UTCEPSS rescoreEPSS 2.6% · 85th percentile
- 2026-10-22 03:39 UTCEG score recompute
- 2026-10-21 16:28 UTCEPSS rescoreEPSS 2.6% · 85th percentile
- 2026-10-21 04:35 UTCEG score recompute
- 2026-10-20 16:28 UTCEPSS rescoreEPSS 2.6% · 85th percentile
- 2026-10-20 05:30 UTCEG score recompute
- 2026-10-19 16:28 UTCEPSS rescoreEPSS 2.6% · 85th percentile
- 2026-10-19 06:25 UTCEG score recompute
- 2026-10-18 16:28 UTCEPSS rescoreEPSS 2.6% · 85th percentile
- 2026-10-18 07:17 UTCEG score recompute
- 2026-10-17 16:29 UTCEPSS rescoreEPSS 2.6% · 85th percentile
- 2026-10-17 08:10 UTCEG score recompute
- 2026-10-16 16:33 UTCEPSS rescoreEPSS 2.6% · 85th percentile
- 2026-10-16 09:03 UTCEG score recompute
- 2026-10-15 16:28 UTCEPSS rescoreEPSS 2.6% · 85th percentile
- 2026-10-15 08:20 UTCEG score recompute
- 2026-10-14 16:28 UTCEPSS rescoreEPSS 2.6% · 85th percentile
- 2026-10-14 04:37 UTCEG score recompute
- 2026-10-13 16:28 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-10-12 19:16 UTCEG score recompute
- 2026-10-12 16:29 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-10-11 23:41 UTCEG score recompute
- 2026-10-11 13:43 UTCEPSS rescoreEPSS 2.6% · 84th percentile
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- 2026-10-10 19:56 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-10-09 20:04 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-10-09 19:55 UTCOSV refresh
- 2026-10-08 16:39 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-10-07 23:44 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-10-06 15:14 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-10-05 17:40 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-10-03 14:22 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-10-01 19:46 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-30 15:36 UTCEG score recompute
- 2026-09-30 15:00 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-29 15:15 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-28 13:47 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-27 13:41 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-26 15:54 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-26 00:21 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-24 14:00 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-23 13:44 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-22 14:44 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-21 20:28 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-20 20:12 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-20 03:20 UTCOSV refresh
- 2026-09-19 15:38 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-18 19:23 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-17 19:23 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-16 14:05 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-15 03:06 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-13 16:43 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-12 14:57 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-11 14:49 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-11 09:33 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-08 21:56 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-07 15:58 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-06 13:45 UTCEPSS rescoreEPSS 2.6% · 84th percentile
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- 2026-09-04 13:57 UTCEPSS rescoreEPSS 2.6% · 84th percentile
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- 2026-09-02 14:08 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-01 13:50 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-09-01 07:22 UTCOSV refresh
- 2026-09-01 03:32 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-30 19:14 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-30 01:19 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-28 21:37 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-27 14:22 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-26 14:42 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-25 13:46 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-24 14:13 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-23 00:16 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-21 23:46 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-20 22:52 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-19 17:01 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-18 13:45 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-17 13:44 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-16 14:53 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-16 02:11 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-15 06:37 UTCOSV refresh
- 2026-08-15 01:27 UTCEPSS rescoreEPSS 2.6% · 84th percentile
- 2026-08-13 21:57 UTCEPSS rescoreEPSS 2.6% · 83rd percentile
- 2026-08-12 13:48 UTCEPSS rescoreEPSS 2.6% · 83rd percentile
- 2026-08-11 13:38 UTCEPSS rescoreEPSS 2.6% · 83rd percentile
- 2026-08-08 16:33 UTCEPSS rescoreEPSS 2.6% · 83rd percentile
- 2026-08-07 16:24 UTCEPSS rescoreEPSS 2.6% · 83rd percentile
- 2026-08-06 13:43 UTCEPSS rescoreEPSS 2.6% · 83rd percentile
- 2026-08-05 19:14 UTCEPSS rescoreEPSS 2.6% · 83rd percentile
- 2026-08-04 15:06 UTCEPSS rescoreEPSS 2.6% · 83rd percentile
- 2026-08-04 10:34 UTCEPSS rescoreEPSS 2.6% · 83rd percentile
- 2026-08-03 10:33 UTCEPSS rescoreEPSS 2.6% · 83rd percentile
- 2026-08-02 02:24 UTCEPSS rescoreEPSS 2.6% · 83rd percentile
Related CVEs(same CWE)
Same CWE
10 shownCWE-829
Frequently asked(5)
What is CVE-2021-32802?
When was the CVE record for CVE-2021-32802 published?
Is CVE-2021-32802 actively exploited?
What is the CVSS score of CVE-2021-32802?
How do I remediate CVE-2021-32802?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2021-32802
Is Your Infrastructure Affected by CVE-2021-32802?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.