CVE-2026-77910
High
Description
Incorrect authorization in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
SeverityHigh
CVSS8.8
Exploit probability—
Product
Microsoft Exchange Server 2016 Cumulative Update 23
PublishedOct 13, 2026
First seenOct 13, 2026
Weakness typeCWE-863Incorrect authorization
How to fix
Update
- Microsoft Microsoft Exchange Server 2016 Cumulative Update 2315.01.2507.077 or later
- Microsoft Microsoft Exchange Server 2019 Cumulative Update 1415.02.1544.050 or later
- Microsoft Microsoft Exchange Server 2019 Cumulative Update 1515.02.1748.055 or later
- Microsoft Microsoft Exchange Server Subscription Edition RTM15.02.2562.056 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Microsoft Microsoft Exchange Server 2016 Cumulative Update 23 | 15.01.0.0 ≤ v < 15.01.2507.077 | 15.01.2507.077 |
| Microsoft Microsoft Exchange Server 2019 Cumulative Update 14 | 15.02.0.0 ≤ v < 15.02.1544.050 | 15.02.1544.050 |
| Microsoft Microsoft Exchange Server 2019 Cumulative Update 15 | 15.02.0.0 ≤ v < 15.02.1748.055 | 15.02.1748.055 |
| Microsoft Microsoft Exchange Server Subscription Edition RTM | 15.02.0.0 ≤ v < 15.02.2562.056 | 15.02.2562.056 |
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