Which products and versions are affected by CVE-2020-5810?

Affected: Umbraco CMS versions >= <= 8.9.1 or current (unfixed). The full list is in the CVE brief.

Is CVE-2020-5810 being exploited in the wild?

It is not listed in any known-exploited vulnerabilities catalog.

Is CVE-2020-5810 in the CISA KEV catalog?

No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.

Is there a public exploit for CVE-2020-5810?

No public exploit code is known.

Is there a fix for CVE-2020-5810?

Fixed versions are available, including Umbraco CMS <=8.9.1, Umbraco CMS 8.9.1.

How urgently should CVE-2020-5810 be patched?

Brandefense priority: patch immediately, because it is very likely to be exploited soon.

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Vulnerability Intelligence

CVE-2020-5810

Q: What is CVE-2020-5810?

A stored XSS vulnerability exists in Umbraco CMS <= 8.9.1 or current.

Q: Is CVE-2020-5810 being exploited in the wild?

It is not listed in any known-exploited vulnerabilities catalog.

Q: Is CVE-2020-5810 in the CISA KEV catalog?

No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.

Q: Is there a public exploit for CVE-2020-5810?

No public exploit code is known.

Q: Is there a fix for CVE-2020-5810?

Fixed versions are available, including Umbraco CMS <=8.9.1, Umbraco CMS 8.9.1.

Q: How urgently should CVE-2020-5810 be patched?

Brandefense priority: patch immediately, because it is very likely to be exploited soon.

Medium

A stored XSS vulnerability exists in Umbraco CMS <= 8.9.1 or current.

Published Dec 30, 2020 · Updated Jul 8, 2026

Key Facts

Patch immediately

CVE-2020-5810 is a medium-severity vulnerability (CVSS 5.4 v3.1) affecting Umbraco CMS.
It is not listed in any known-exploited vulnerabilities catalog. No public exploit code is known.
EPSS estimates a 62% probability of exploitation in the next 30 days.
Fixed versions are available, including Umbraco CMS <=8.9.1, Umbraco CMS 8.9.1.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.

CVSS v3.1

5.4

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

EPSS (30-day exploit likelihood)

62%

Higher than 99.1% of all scored CVEs

Exploited in the wild

No known

Not in a known-exploited catalog

Public exploit code

None known

Get the full CVE-2020-5810 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

Description

A stored XSS vulnerability exists in Umbraco CMS <= 8.9.1 or current. An authenticated user authorized to upload media can upload a malicious .svg file which act as a stored XSS payload.

Affected Products

2 affected entries in total

Product	Affected versions	Fixed in
Umbraco CMSUmbraco	>= <= 8.9.1 or current (unfixed)	8.9.1

Patched Releases

Umbraco CMS

<=8.9.1

Timeline

Publicly disclosed
Dec 30, 2020
Last updated
Jul 8, 2026

Weakness Type

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

References

exploithttps://www.tenable.com/security/research/tra-2020-59

FAQ

Common Questions.

A stored XSS vulnerability exists in Umbraco CMS <= 8.9.1 or current.
Affected: Umbraco CMS versions >= <= 8.9.1 or current (unfixed). The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including Umbraco CMS <=8.9.1, Umbraco CMS 8.9.1.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.

Is CVE-2020-5810 Running On Your Attack Surface?

Brandefense maps vulnerabilities like this one to your internet-facing assets and tells you exactly where to patch.

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