SB2026021093 - Multiple vulnerabilities in Microsoft Outlook

Description

This security bulletin contains information about 2 secuirty vulnerabilities.

1) Information disclosure (CVE-ID: CVE-2026-21260)

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to excessive data output by the application in Microsoft Outlook. A remote attacker can use a specially crafted email and gain unauthorized access to sensitive information on the system.

2) Deserialization of Untrusted Data (CVE-ID: CVE-2026-21511)

The vulnerability allows a remote attacker to compromise the target system.

The vulnerability exists due to insecure input validation when processing serialized data in Microsoft Outlook. A remote attacker can pass specially crafted data to the application and gain access to sensitive information.

Remediation

Install update from vendor's website.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21260
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21511