CVE-2026-55008 in Exchange Server
Summary
by MITRE • 07/14/2026
Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.
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Analysis
by VulDB Data Team • 07/15/2026
Cross site scripting vulnerabilities in microsoft exchange server represent a critical security weakness that enables unauthorized attackers to inject malicious scripts into web pages viewed by users. this flaw exists within the web page generation process where input validation and sanitization mechanisms fail to properly neutralize potentially dangerous user-supplied data before rendering it in web interfaces. the vulnerability stems from inadequate filtering of input parameters that are processed through the exchange server's web-based administration and client access components, creating opportunities for attackers to exploit the system through malicious script injection attacks.
the technical implementation of this cross site scripting flaw allows threat actors to manipulate web page content by injecting malicious javascript code through various input vectors including email headers, message bodies, or administrative interfaces. when legitimate users browse pages containing this malicious content, their browsers execute the injected scripts in the context of the vulnerable exchange server, potentially compromising user sessions and enabling unauthorized access to sensitive email data. the vulnerability specifically affects the server's web-based management tools and client access services where user input is not properly escaped or validated before being rendered back to web clients.
the operational impact of this vulnerability extends beyond simple session hijacking to encompass comprehensive data exfiltration capabilities and persistent access to corporate email infrastructure. attackers can leverage this weakness to steal authentication tokens, access user mailboxes, modify email content, and potentially escalate privileges within the exchange environment. organizations using affected exchange server versions face significant risk of credential theft and unauthorized data access, particularly when administrators interact with web-based management interfaces or when users receive malicious emails containing crafted payloads designed to exploit this vulnerability.
mitigation strategies for this cross site scripting vulnerability should include immediate deployment of microsoft security patches and updates addressing the specific flaw in exchange server web components. organizations must implement comprehensive input validation across all user-facing web interfaces and ensure proper output encoding for all dynamic content generated by the exchange server. network segmentation and privileged access controls can help limit the potential impact of successful exploitation attempts, while regular monitoring of web application logs should be implemented to detect suspicious activities related to script injection attempts. security teams should also consider implementing web application firewalls to provide additional protection layers against cross site scripting attacks targeting exchange server web interfaces.
this vulnerability aligns with common weakness enumeration category 79 which specifically addresses cross site scripting flaws in web applications, and maps to attack technique t1566 within the attack framework focusing on social engineering through malicious email content. organizations should conduct thorough security assessments of their exchange server configurations and implement defense in depth strategies that include regular vulnerability scanning, penetration testing, and user awareness training to prevent exploitation of such web application flaws.