Vulnerability · Published Jul 14, 2026 · Assigned by microsoft
CVE-2026-55005Microsoft Exchange Server Remote Code Execution Vulnerability
High 8.8
In plain English
A high-severity heap buffer overflow in Microsoft Exchange Server 2016 Cumulative Update 23 from Microsoft. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.0% (higher than 63% of all known vulnerabilities).
Severity (CVSS 3.1)8.8High
Exploit odds (30 days)1.0%top 36.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Heap-based buffer overflow in Microsoft Exchange Server allows an authorized attacker to execute code over a network.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Microsoft Exchange Server 2016 Cumulative Update 23 | 15.01.0.0 – before 15.01.2507.071 |
| Microsoft | Microsoft Exchange Server 2019 Cumulative Update 14 | 15.02.0.0 – before 15.02.1544.043 |
| Microsoft | Microsoft Exchange Server 2019 Cumulative Update 15 | 15.02.0.0 – before 15.02.1748.048 |
| Microsoft | Microsoft Exchange Server Subscription Edition RTM | 15.02.0.0 – before 15.02.2562.045 |
Weakness: CWE-122 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
References
- Microsoft Exchange Server Remote Code Execution Vulnerability vendor-advisory, patch