What is the CVSS score of CVE-2020-5809?

CVE-2020-5809 has a CVSS 3.1 base score of 5.4 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N. EPSS exploitation probability: 0.7%.

Is there a public PoC exploit available for CVE-2020-5809?

Yes, a public proof-of-concept exploit is available for CVE-2020-5809. Prioritise patching immediately. EPSS: 0.7%.

Umbraco Cms CVE-2020-5809

MEDIUM

Cross-site Scripting (XSS) (CWE-79)

2020-12-30 vulnreport@tenable.com

XSS Umbraco Cms

5.4

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

5.4 MEDIUM

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Lifecycle Timeline

CVE Published

Dec 30, 2020 - 16:15 nvd

MEDIUM 5.4

DescriptionNVD

A stored XSS vulnerability exists in Umbraco CMS <= 8.9.1 or current. An authenticated user can inject arbitrary JavaScript code into iframes when editing content using the TinyMCE rich-text editor, as TinyMCE is configured to allow iframes by default in Umbraco CMS.

AnalysisAI

A stored XSS vulnerability exists in Umbraco CMS <= 8.9.1 or current. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified as Cross-Site Scripting (XSS) (CWE-79), which allows attackers to inject malicious scripts into web pages viewed by other users. A stored XSS vulnerability exists in Umbraco CMS <= 8.9.1 or current. An authenticated user can inject arbitrary JavaScript code into iframes when editing content using the TinyMCE rich-text editor, as TinyMCE is configured to allow iframes by default in Umbraco CMS. Affected products include: Umbraco Umbraco Cms.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Sanitize all user input, use Content-Security-Policy headers, encode output contextually (HTML, JS, URL). Use frameworks with built-in XSS protection.