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critical · CVSS v3 8.8

CVE-2026-108446

A use‑after‑free vulnerability in Microsoft Office Excel can be triggered by a crafted file, allowing an attacker to execute arbitrary code

Overview

A use‑after‑free vulnerability in Microsoft Office Excel can be triggered by a crafted file, allowing an attacker to execute arbitrary code on a victim’s machine. The flaw is exploitable over a network when the file is opened remotely. It is rated critical due to the high impact and ease of exploitation.

Description

Use after free in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.

Impact

Confidentiality: attackers can exfiltrate data; Integrity: they can modify documents; Availability: they can crash Excel or the host. The vulnerability affects all users running vulnerable versions of Excel, especially those who open files from untrusted sources over a network.

Remediation

Apply the latest security update for Microsoft Office Excel released by Microsoft. Disable macros and enable the 'Protected View' setting for files from the internet. Ensure that the Office installation is up to date and that network file sharing is restricted to trusted users.

Risk context

Severity is critical with CVSS 8.8. No EPSS data available. The flaw can be exploited remotely with no user interaction, making it urgent for organizations to patch immediately.

Affected products

  • Microsoft Office Excel 365
  • Microsoft Office Excel 2019
  • Microsoft Office Excel 2021
  • Microsoft Office Excel 2024

Scores

Severity
critical
CVSS v2
10
CVSS v3
8.8
CVSS v4
—
EPSS
—

use-after-free Excel remote-code-execution critical Microsoft Office network-exploit patch

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