What is CVE-2020-5575?

CVE-2020-5575 is a medium-severity vulnerability in Sixapart Movable Type, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2020-05-14.

How severe is CVE-2020-5575?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Sixapart Movable Type

CVE-2020-5575

Cross-site scripting vulnerability in Movable Type series (Movable Type 7 r.4606 (7.2.1) and earlier (Movable Type 7), Movable Type Advanced 7 r.4606 (7.2.1) and earlier (Movable Type Advanced 7), Movable Type for AWS 7 r.4606 (7.2.1) and earlier (Movable Type for AWS 7), Movable Type 6.5.3 and earlier (Movable Type 6.5), Movable Type Advanced 6.5.3 and earlier (Movable Type Advanced 6.5), Movable Type 6.3.11 and earlier (Movable Type 6.3), Movable Type Advanced 6.3.11 and earlier (Movable Type 6.3), Movable Type Premium 1.29 and earlier, and Movable Type Premium Advanced 1.29 and earlier) allows remote attackers to inject arbitrary script or HTML via unspecified vectors.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2020-05-14 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.009 (59.7th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 60th percentile — 59.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

Sixapart Movable Type
Six Apart Ltd. Movable Type — versions Movable Type 7 r.4606 (7.2.1) and earlier (Movable Type 7), Movable Type Advanced 7 r.4606 (7.2.1) and earlier (Movable Type Advanced 7), Movable Type for AWS 7 r.4606 (7.2.1) and earlier (Movable Type for AWS 7), Movable Type 6.5.3 and earlier (Movable Type 6.5), Movable Type Advanced 6.5.3 and earlier (Movable Type Advanced 6.5), Movable Type 6.3.11 and earlier (Movable Type 6.3), Movable Type Advanced 6.3.11 and earlier (Movable Type 6.3), Movable Type Premium 1.29 and earlier, and Movable Type Premium Advanced 1.29 and earlier

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

movabletype.org/news/2020/05/mt-730-660-6312-released.html (Release Notes, Vendor Advisory)
jvn.jp/en/jp/JVN28806943/index.html (VDB Entry, Third Party Advisory)

Frequently asked questions

What is CVE-2020-5575?: CVE-2020-5575 is a medium-severity vulnerability in Sixapart Movable Type, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2020-05-14.
How severe is CVE-2020-5575?: Medium severity. CVSS v3 base score is 6.1 out of 10.