Heap-based buffer overflow in Microsoft Exchange Server - CVE-2026-55005
Published: July 16, 2026
Vulnerability identifier: #VU137890
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-55005
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to a boundary error in Microsoft Exchange Server. A remote user can pass specially crafted data to the application, trigger a heap-based buffer overflow and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
Affected software
Microsoft Exchange Server
How to mitigate CVE-2026-55005
Install updates from vendor's website.
Microsoft Exchange Server - addressed in versions SE RTM Jul26SU 15.02.2562.045, 2016 CU23 Jul26SU 15.01.2507.071, 2019 CU14 Jul26SU 15.02.1544.043, 2019 CU15 Jul26SU 15.02.1748.048