CVE-2020-20691

Name: CVE-2020-20691
Creator: NVD / NIST
Published: 2021-09-27T22:15:07.477+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.90%

Last modified Jun 17, 2026

CVE-2020-20691 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. An issue in Monstra CMS v3.0.4 allows attackers to execute arbitrary web scripts or HTML via bypassing the file extension filter and uploading crafted HTML files.. EPSS estimates a 0.90% chance of exploitation in the next 30 days.

Description

An issue in Monstra CMS v3.0.4 allows attackers to execute arbitrary web scripts or HTML via bypassing the file extension filter and uploading crafted HTML files.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

0.90%

55.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-434

Affected Software

Vendor	Product	Versions
Monstra	Monstra Cms	3.0.4

References

https://github.com/monstra-cms/monstra/issues/461Exploit, Issue Tracking, Third Party Advisory
https://github.com/monstra-cms/monstra/issues/461Exploit, Issue Tracking, Third Party Advisory

Timeline

Published: Sep 27, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-20691?

An issue in Monstra CMS v3.0.4 allows attackers to execute arbitrary web scripts or HTML via bypassing the file extension filter and uploading crafted HTML files.

How severe is CVE-2020-20691?

CVE-2020-20691 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.90% probability of exploitation in the next 30 days.

How do I fix CVE-2020-20691?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-20691?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST