Microsoft Exchange Server Flaws Enabled Spoofing, Security Bypass, and SYSTEM-Level Access
Microsoft disclosed multiple vulnerabilities in on-premises Exchange Server, including CVE-2021-31207 (security feature bypass), CVE-2021-31209 (spoofing), and CVE-2022-41040 (elevation of privilege). The issues affected Exchange deployments rather than Exchange Online, extending a pattern of high-impact weaknesses in the mail platform that could undermine trust boundaries, enable impersonation, and weaken built-in protections.
Among them, CVE-2022-41040 was rated Critical with a CVSS 3.1 score of 8.8, and Microsoft said exploitation had been detected in the wild before public disclosure. The flaw required an authenticated attacker with low privileges and no user interaction, and successful exploitation could allow the attacker to run PowerShell as SYSTEM. Microsoft later released security updates and directed Exchange Server customers to apply mitigations and patches for the reported zero-day issues.
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How this story unfolded
3 events from the most recent confirmed update back to the earliest known activity.
Microsoft releases security updates for CVE-2022-41040
Microsoft later released security updates addressing CVE-2022-41040. The fixes were made available on 2022-11-08.
Microsoft discloses Exchange Server vulnerability CVE-2022-41040
Microsoft disclosed CVE-2022-41040, an elevation-of-privilege vulnerability affecting Microsoft Exchange Server. Microsoft said exploitation had been detected in the wild and advised Exchange Server customers to follow mitigation guidance for the reported Exchange zero-days.
Microsoft publishes Exchange Server fixes for CVE-2021-31207 and CVE-2021-31209
Microsoft listed CVE-2021-31207, a Microsoft Exchange Server security feature bypass vulnerability, and CVE-2021-31209, a Microsoft Exchange Server spoofing vulnerability, in its Security Update Guide. Both advisories were published on 2021-05-11.
Sources
3 references tracked. Mallory keeps watching after this page renders.
CVE-2022-41040 - Security Update Guide - Microsoft - Microsoft Exchange Server Elevation of Privilege Vulnerability
portal.msrc.microsoft.com
Open sourceCVE-2021-31207 - Security Update Guide - Microsoft - Microsoft Exchange Server Security Feature Bypass Vulnerability
msrc.microsoft.com
Open sourceCVE-2021-31209 - Security Update Guide - Microsoft - Microsoft Exchange Server Spoofing Vulnerability
msrc.microsoft.com
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Microsoft Exchange Server Elevation of Privilege Flaws Prompt Repeated Patching
Microsoft has disclosed multiple **elevation of privilege** vulnerabilities affecting **Microsoft Exchange Server**, including `CVE-2021-34470`, `CVE-2021-41348`, `CVE-2022-41123`, and `CVE-2025-64666`, indicating a recurring security issue in the on-premises mail platform across several release cycles. The advisories show Exchange continued to receive fixes for privilege-escalation weaknesses over multiple years, with Microsoft publishing separate Security Update Guide entries as new flaws were identified. Among the listed issues, Microsoft provided the most detail for `CVE-2021-34470`, rating it **Important** with a **CVSS 3.0 score of 8.0** and describing it as requiring access from a logically adjacent network. Microsoft said the flaw required a **schema change** and was fixed for **Exchange Server 2019** and **Exchange Server 2016** in cumulative updates released on June 29, 2021; at initial publication, the company said it was **not publicly disclosed**, **not exploited**, and **less likely to be exploited**. A separate Microsoft advisory in the same reference set, `CVE-2026-26128`, affects the **Windows SMB Server** rather than Exchange and also involves elevation of privilege.
May 25, 2026
Microsoft Exchange Server Spoofing Flaws Tracked Across Multiple CVEs
Microsoft has published Security Update Guide entries for multiple **Microsoft Exchange Server spoofing vulnerabilities**, including `CVE-2021-1730`, `CVE-2024-49040`, and `CVE-2025-64667`. The references indicate a recurring class of flaws affecting Exchange Server in which an attacker could impersonate a trusted source or manipulate how identities or messages are presented, creating opportunities for phishing, fraud, or follow-on compromise in enterprise email environments. The available advisories provide limited public technical detail, but the repeated publication of Exchange spoofing CVEs shows that Microsoft continues to track and remediate this attack surface through its update program. For defenders, the immediate implication is to review Exchange Server exposure, validate that relevant Microsoft security updates tied to these CVEs have been applied, and monitor mail infrastructure for signs of spoofed communications or abuse of trust relationships involving Exchange services.
May 25, 2026
Microsoft discloses multiple spoofing flaws in Exchange Server and OfficePlus
Microsoft published security advisories for several spoofing vulnerabilities affecting **Microsoft Exchange Server** and **Microsoft OfficePlus**, identifying `CVE-2021-41350`, `CVE-2021-42305`, `CVE-2022-41078`, `CVE-2022-41079`, and `CVE-2025-55243`. The Exchange issues span multiple advisory releases and indicate a recurring class of flaws that could allow attackers to impersonate trusted senders, services, or content within enterprise messaging environments. The disclosures show Exchange Server as the primary affected platform, with four separate spoofing CVEs listed across 2021 and 2022, while a later advisory extends the same risk category to OfficePlus. Although the referenced notices provide limited public technical detail, the affected products are widely deployed in corporate communications workflows, making spoofing weaknesses operationally significant for phishing, fraud, and trust-boundary bypass scenarios until patches are applied.
May 25, 2026