CVE-2026-21393

Severity CVSS v4.0:

MEDIUM

Type:

CWE-79 Cross-Site Scripting (XSS)

Publication date:

04/02/2026

Last modified:

04/02/2026

Description

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&#39;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.

Impact

Vector 4.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N CVSS v4.0 Severity and Metrics:

Base Score: 4.80 MEDIUM
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): Low
User Interaction (UI): Active
Confidentiality (VC): None
Integrity (VI): None
Availability (VA): None
Confidentiality (SC): Low
Integrity (SI): Low
Availability (SA): None

Base Score 4.0

4.80

Severity 4.0

MEDIUM

Vector 3.x

CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N CVSS v3.1 Severity and Metrics:

Base Score: 5.40 MEDIUM
Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): Required
Scope (S): Changed
Confidentiality (C): Low
Integrity (I): Low
Availability (A): None

Base Score 3.x

5.40

Severity 3.x

MEDIUM

CVE-2026-21393

Description

Impact

References to Advisories, Solutions, and Tools