SB2026020430 - Multiple vulnerabilities in Six Apart Movable Type
Published: February 4, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 4 secuirty vulnerabilities.
1) Stored cross-site scripting (CVE-ID: CVE-2026-21393)
The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.
The vulnerability exists due to insufficient sanitization of user-supplied data in Edit Comment. A remote user can inject and execute arbitrary HTML and script code in user's browser in context of vulnerable website.
Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.
2) Stored cross-site scripting (CVE-ID: CVE-2026-22875)
The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.
The vulnerability exists due to insufficient sanitization of user-supplied data in Export Sites. A remote user can inject and execute arbitrary HTML and script code in user's browser in context of vulnerable website.
Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.
3) Arbitrary file upload (CVE-ID: CVE-2026-23704)
The vulnerability allows a remote attacker to compromise vulnerable system.
The vulnerability exists due to insufficient validation of file during file upload. A remote user can upload a malicious file and execute it on the server.
4) Improper Neutralization of Formula Elements in a CSV File (CVE-ID: CVE-2026-24447)
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to improper neutralization of formula elements in a CSV file. A remote user can trick a victim to open a specially crafted CSV file and execute arbitrary code on the system.
Remediation
Install update from vendor's website.