Microsoft Exchange Server Vulnerabilities Let Attackers Spoof and Tamper Over Network

Critical security vulnerabilities in Microsoft Exchange Server enable attackers to perform spoofing and tampering attacks over network connections. 

The vulnerabilities include two Exchange Server flaws (CVE-2025-25007 and CVE-2025-25005) enabling spoofing and tampering attacks, plus a Windows Graphics Component elevation of privilege vulnerability (CVE-2025-49743) that could facilitate privilege escalation attacks.

Key Takeaways
1. CVE-2025-25007/25005 enables network spoofing and tampering attacks.
2. CVE-2025-49743 allows SYSTEM access via race conditions.
3. Microsoft updates released August 12, 2025 - deploy urgently.

Spoofing and Tampering Vulnerabilities 

CVE-2025-25007 represents a spoofing vulnerability in Microsoft Exchange Server caused by improper validation of the syntactic correctness of input, classified under CWE-1286. 

This network-based vulnerability requires no privileges or user interaction, earning a CVSS score of 5.3 with the attack vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:U/RL:O/RC:C. 

Successful exploitation allows attackers to spoof incorrect 5322.From email addresses displayed to users, compromising email authenticity.

The second Exchange vulnerability, CVE-2025-25005, enables tampering attacks through improper input validation (CWE-20). 

With a higher CVSS score of 6.5 and vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C, this vulnerability requires low-level privileges but delivers high confidentiality impact. 

Both Exchange vulnerabilities affect multiple versions, including Exchange Server 2016 CU23, Exchange Server 2019 CU14/CU15, and Exchange Server Subscription Edition RTM.

Windows Graphics Component Privilege Escalation

CVE-2025-49743 affects the Windows Graphics Component and represents a more complex attack vector involving concurrent execution using shared resources with improper synchronization. 

This vulnerability combines two critical weaknesses: CWE-362 (Race Condition) and CWE-416 (Use After Free), creating a dangerous privilege escalation opportunity with a CVSS score of 6.7 and a vector string of CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C.

The vulnerability requires winning a race condition, making the attack complexity “High” but potentially granting SYSTEM privileges upon successful exploitation. 

Microsoft’s exploitability assessment rates this as “Exploitation More Likely” compared to the Exchange vulnerabilities, indicating higher risk despite the complex exploitation requirements.

Mitigations

Microsoft released coordinated security updates addressing all three vulnerabilities across affected platforms. 

Server updates include KB5063221, KB5063222, KB5063223, and KB5063224, while Windows systems receive updates ranging from legacy Windows Server 2008 to the latest Windows 11 Version 24H2 and Windows Server 2025.

The Windows Graphics vulnerability affects an extensive range of systems, including Windows 10 versions 1607-22H2, Windows 11 versions 22H2- 24H2, and Windows Server versions 2008-2025. 

Organizations should prioritize immediate patch deployment given the combination of network-based Exchange attacks and local privilege escalation capabilities that could enable sophisticated multi-stage attacks against enterprise infrastructure.

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