CVE-2026-21393

EUVD-2026-5437
Movable Type contains a stored cross-site scripting vulnerability in Edit Comment. If crafted input is stored by an attacker, arbitrary script may be executed on a logged-in user's web browser. Note that Movable Type 7 series and 8.4 series, which are End-of-Life (EOL), are affected by the vulnerability as well.
Cross-site Scripting
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
5.4 MEDIUM
NETWORK
LOW
LOW
CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
jpcertCNA
5.4 MEDIUM
CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Awaiting analysis
This vulnerability is currently awaiting analysis.
Base Score
CVSS 3.x
EPSS Score
Percentile: 1%
Common Weakness Enumeration
References
https://jvn.jp/en/jp/JVN45405689/
https://movabletype.org/news/2026/02/mt-906-released.html
https://www.sixapart.jp/movabletype/news/2026/02/04-1100.html