Local privilege escalation via use-after-free
Published May 12, 2026 · Updated May 12, 2026
Use-after-free in Microsoft Office Click-To-Run allows local users with existing access to elevate privileges on affected Office installations. Microsoft identifies Click-To-Run as the affected component but has not disclosed the freed object's lifetime error or the operation that reuses it. Exploitation requires low-privileged local access and no user interaction, and successful abuse grants elevated control over the affected system.
Summary
What happened
Use-after-free in Microsoft Office Click-To-Run allows local users with existing access to elevate privileges on affected Office installations. Microsoft identifies Click-To-Run as the affected component but has not disclosed the freed object's lifetime error or the operation that reuses it. Exploitation requires low-privileged local access and no user interaction, and successful abuse grants elevated control over the affected system.
The record
- CVE
- CVE-2026-40418
- Published
- May 12, 2026
- Updated
- May 12, 2026
- Vendor
- Microsoft
- Product
- Microsoft Office 2019
- Classifications
- CWE-416, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 12, 2026CVE publishedPublication date reported by the CVE source.
- May 12, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=19.0.0 <https://aka.ms/OfficeSecurityReleases
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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