CVE-2021-20815

6.1 mediumEPSS 0.9%

Medium (6.1) in sixapart movable type. EPSS 0.9% chance of exploitation in the next 30 days.

Cross-site scripting vulnerability in Edit Boilerplate screen of Movable Type (Movable Type 7 r.4903 and earlier (Movable Type 7 Series), Movable Type 6.8.0 and earlier (Movable Type 6 Series), Movable Type Advanced 7 r.4903 and earlier (Movable Type Advanced 7 Series), Movable Type Premium 1.44 and earlier, and Movable Type Premium Advanced 1.44 and earlier) allows remote attackers to inject arbitrary script or HTML via unspecified vectors.

Severity

CVSS 3.1

6.1 medium

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

EPSS: 0.9% chance of exploitation in the next 30 days; higher than 59% of CVEs (scores of 2026-11-01)
CWE: CWE-79
Published: 2021-08-26
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

sixapart:movable_type

References

https://jvn.jp/en/jp/JVN97545738/index.html
https://movabletype.org/news/2021/08/mt-780-681-released.html
https://jvn.jp/en/jp/JVN97545738/index.html
https://movabletype.org/news/2021/08/mt-780-681-released.html

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