PT-2026-6098 · Six Apart · Movable Type

Kentaro Ishii · Published 2026-02-04 · Updated 2026-02-04 · CVE-2026-21393

Positive Technologies (AI Summary)

CVSS v3.1

5.4

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions Movable Type versions 7.x and 8.4.x

Description Movable Type has a stored cross-site scripting issue in the Edit Comment functionality. An attacker could execute arbitrary script in a logged-in user’s web browser by storing crafted input. The Edit Comment functionality is susceptible to this issue.

Recommendations Versions prior to 7.x and 8.4.x are recommended.

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2026-21393

Affected Products

Movable Type

References · 5

• https://nvd.nist.gov/vuln/detail/CVE-2026-21393 · Security Note
• https://sixapart.jp/movabletype/news/2026/02/04-1100.html · Note
• https://jvn.jp/en/jp/JVN45405689 · Note
• https://movabletype.org/news/2026/02/mt-906-released.html · Note
• https://t.me/CVEtracker/43692 · Telegram Post