SB2025011454 - Multiple vulnerabilities in Microsoft SharePoint Server

Description

This security bulletin contains information about 3 secuirty vulnerabilities.

1) Cross-site scripting (CVE-ID: CVE-2025-21393)

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 Microsoft SharePoint Server. A remote user can trick the victim to follow a specially crafted link 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) Improper Authorization (CVE-ID: CVE-2025-21348)

The vulnerability allows a remote user to bypass authorization checks.

The vulnerability exists due to insufficient authorization controls in Microsoft SharePoint Server. A remote administrator can execute arbitrary code on the target system.

3) Input validation error (CVE-ID: CVE-2025-21344)

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to insufficient validation of user-supplied input in Microsoft SharePoint Server. A remote attacker can trick a victim to open a specially crafted file and execute arbitrary code on the system.

Remediation

Install update from vendor's website.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-21393
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-21348
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-21344