SB2025011477 - Multiple vulnerabilities in Microsoft Outlook

Description

This security bulletin contains information about 2 vulnerabilities.

1) Improper Restriction of Names for Files and Other Resources (CVE-ID: CVE-2025-21361)

CWE-ID: CWE-641 - Improper Restriction of Names for Files and Other Resources

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber

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

The vulnerability exists due to improper restriction of names for files and other resources in Microsoft Outlook. A remote attacker can trick a victim to open a specially crafted file and execute arbitrary code on the target system.

2) Use of uninitialized resource (CVE-ID: CVE-2025-21357)

CWE-ID: CWE-908 - Use of Uninitialized Resource

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to bypass certain security restrictions.

The vulnerability exists due to usage of uninitialized resources Microsoft Outlook. A remote user can trick a victim to open a specially crafted file, trigger uninitialized usage of resources and execute arbitrary code on the target system.

Remediation

Install update from vendor's website.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-21361
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-21357