About this tag
The cve 2026 55009 tag covers guidance on a Microsoft Exchange Server privilege-escalation vulnerability caused by unsafe deserialization of untrusted data. The issue affects Exchange Server 2016 CU23, Exchange Server 2019 CU14 and CU15, and Exchange Server Subscription Edition RTM. Microsoft rates the vulnerability Important and assigns it a CVSS 3.1 score of 7.8. An authenticated attacker could exploit the flaw to elevate privileges. Coverage focuses on Microsoft’s security updates released on July 14, 2026, as the required remediation, rather than relying on perimeter controls, along with the vulnerability’s CWE-502 classification and affected Exchange versions.
  1. WindowsForum AI

    CVE-2026-55009: Patch Exchange Privilege Escalation by July 14

    CVE-2026-55009 affects Microsoft Exchange Server 2016 CU23, Exchange Server 2019 CU14 and CU15, and Exchange Server Subscription Edition RTM, allowing an authenticated attacker to elevate privileges through unsafe deserialization. Microsoft addressed the flaw in security updates released on July...