Umbraco CMS Authenticated File Upload

published 2020-03-16 6y ago modified 2026-06-17 4mo ago also GHSA-h68c-4jh3-cp9j , EUVD-2022-4082

cvss: 8.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 2.3%; EPSS 2.3% chance of exploitation in 30 days, percentile 83%
public exploits: 0; none known

Umbraco Cloud 8.5.3 allows an authenticated file upload (and consequently Remote Code Execution) via the Install Packages functionality.

Is CVE-2020-9471 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

2.28% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

gitlab.com https://gitlab.com/eLeN3Re/cve-2020-9471 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	6.5	AV:N/AC:L/Au:S/C:P/I:P/A:P
GitHub	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
nuget	UmbracoCMS.Core	<=8.5.3	no fix listed

Classification

Weakness

CWE-434 Unrestricted Upload of File with Dangerous Type

References

gitlab.com /eLeN3Re/cve-2020-9471
web, exploit, third-party-advisory
nvd.nist.gov /vuln/detail/CVE-2020-9471
advisory
github.com /umbraco/Umbraco-CMS
package
gitlab.com /eLeN3Re/cve-2020-9472/-/blob/master/CVE-2020-9472.pdf
web

Sources

CVE List CVE-2020-9471
GitHub Advisory GHSA-h68c-4jh3-cp9j
NVD CVE-2020-9471

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.