Summary
Impact: Information Disclosure. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.
Details
What type of information could be disclosed by this vulnerability?
An attacker who successfully exploited this vulnerability could obtain limited memory-related information, specifically a heap address returned by the affected service.
According to the CVSS metric, user interaction is required (UI:R). What interaction would the user have to do?
An attacker must send a user a malicious Office file and convince them to open it.
Is the Preview Pane an attack vector for this vulnerability?
Yes, the Preview Pane is an attack vector.
Security updates
https — https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
16.111.26071215 — https://go.microsoft.com/fwlink/p/?linkid=831049
16.0.5561.1000 — https://support.microsoft.com/help/5002887
16.111.26071215 — https://www.microsoft.com/en-us/microsoft-365/mac/microsoft-365-for-mac?msockid=35f9adb0e74b61392038b90de6fe608c
Vulnerabilities 1
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High 7.1
Microsoft Office Information Disclosure Vulnerability
Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
Revision history
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#1
Information published.
References
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CVE-2026-56193 Microsoft Office Information Disclosure Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56193
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Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
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Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
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Common Vulnerability Scoring System
https://www.first.org/cvss