CVE-2026-78520: Microsoft Office Outlook Information Disclosure Vulnerability
Microsoft Office Outlook Information Disclosure Vulnerability
Other sources
Out-of-bounds read in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 16.0.17932.20976 - Upgrade
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Fixed in 16.0.20326.20138 - Upgrade
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Fixed in 16.0.5569.1000Patch KB5002923 - Upgrade
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Fixed in 16.0.14334.20906 - Upgrade
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Fixed in 16.0.10417.20207 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 16.113.26091433
Event History
Frequently Asked Questions
What does an attacker need to exploit this issue?
The supplied vector indicates network-based exploitation with low attack complexity and no required privileges, but user interaction is required. The description states that an unauthorized attacker may execute code over a network.
Which Office products should be reviewed?
Review deployments of Microsoft Word 2016, Microsoft 365 Apps for Enterprise, Microsoft Office LTSC 2024 for 32-bit and 64-bit editions, Microsoft Office LTSC 2021 for 32-bit and 64-bit editions, Microsoft Office 365 for Mac, and Microsoft Office LTSC for Mac 2024. The supplied data does not identify affected build numbers or update levels.
What security impact is indicated by the provided scoring data?
The vector assigns high confidentiality impact and no integrity or availability impact. It also rates the issue as medium severity with a 6.5 score.