SB2026012659 - Remote code execution in Microsoft Office
Published: January 26, 2026 Updated: February 6, 2026
Security Bulletin ID
SB2026012659
CSH Severity
Critical
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Code execution
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Reliance on Untrusted Inputs in a Security Decision (CVE-ID: CVE-2026-21509)
CWE-ID: CWE-807 - Reliance on Untrusted Inputs in a Security Decision
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Red
The vulnerability allows a remote attacker to compromise the affected system.
The vulnerability exists due to improper insecure handling of OLE objects. A remote attacker can trick the victim into opening a specially crafted Office file and execute arbitrary code on the system.
Note, the vulnerability is being actively exploited in the wild.
Remediation
Install update from vendor's website.