CVE-2021-20665

Name: CVE-2021-20665
Creator: NVD / NIST
Published: 2021-03-05T10:15:12.847+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.81%

Last modified Jun 17, 2026

CVE-2021-20665 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. Cross-site scripting vulnerability in in Add asset screen of Contents field of Movable Type 7 r.4705 and earlier (Movable Type 7 Series), Movable Type Advanced 7 r.4705 and earlier (Movable Type Advanced 7 Series), Movable Type Premium 1.39 and earlier, and Movable Type Premium Advanced 1.39 and earlier allows remote attackers to inject an arbitrary script via unspecified vectors.. EPSS estimates a 0.81% chance of exploitation in the next 30 days.

Description

Cross-site scripting vulnerability in in Add asset screen of Contents field of Movable Type 7 r.4705 and earlier (Movable Type 7 Series), Movable Type Advanced 7 r.4705 and earlier (Movable Type Advanced 7 Series), Movable Type Premium 1.39 and earlier, and Movable Type Premium Advanced 1.39 and earlier allows remote attackers to inject an arbitrary script via unspecified vectors.

Metrics

CVSS 3.1

6.1/10

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

EPSS Probability

0.81%

52.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Movabletype	Movable Type	<= 7.4705
Movabletype	Movable Type Advanced	<= 7.4705
Movabletype	Movable Type Premium	<= 1.39
Movabletype	Movable Type Premium Advanced	<= 1.39

References

https://jvn.jp/en/jp/JVN66542874/index.htmlThird Party Advisory
https://movabletype.org/news/2021/02/mt-760-676-released.htmlRelease Notes, Vendor Advisory
https://jvn.jp/en/jp/JVN66542874/index.htmlThird Party Advisory
https://movabletype.org/news/2021/02/mt-760-676-released.htmlRelease Notes, Vendor Advisory

Timeline

Published: Mar 5, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20665?

How severe is CVE-2021-20665?

CVE-2021-20665 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.81% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20665?

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-2021-20665?

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

Scan your code now

Source: NVD / NIST