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 to elevate privileges on affected 32-bit and x64 Windows systems. Microsoft identifies Click-to-Run as the affected component but has not disclosed the freed object or the code path that later accesses it. Exploitation requires prior local low-privileged access and raises the attacker's privilege level; no remote or macOS exposure is reported.
Summary
What happened
Use-after-free in Microsoft Office Click-to-Run allows local users to elevate privileges on affected 32-bit and x64 Windows systems. Microsoft identifies Click-to-Run as the affected component but has not disclosed the freed object or the code path that later accesses it. Exploitation requires prior local low-privileged access and raises the attacker's privilege level; no remote or macOS exposure is reported.
The record
- CVE
- CVE-2026-40419
- 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
Compare your product and version with the public record. A matching version still requires validation against your environment.
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.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo