CVE-2026-62839 in SharePoint Server
Summary
by MITRE • 08/11/2026
Insufficiently protected credentials in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.
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Analysis
by VulDB Data Team • 08/11/2026
This vulnerability represents a critical security weakness in Microsoft Office SharePoint platforms where authentication credentials are inadequately safeguarded during network transmission and storage operations. The flaw enables malicious actors who have already gained authorized access to the system to exploit weak credential protection mechanisms and conduct sophisticated spoofing attacks against other users within the same network environment. Such vulnerabilities typically arise from insufficient implementation of secure authentication protocols or failure to properly encrypt sensitive credential information during network communication.
The technical root cause of this issue stems from inadequate cryptographic protection of authentication tokens and session identifiers used by SharePoint systems. When credentials are transmitted over networks without proper encryption or when stored in vulnerable formats within the system, attackers can intercept, manipulate, or reuse these authenticators to impersonate legitimate users. This weakness aligns with common CWE categories including weak credential storage and insufficient transport layer protection. The vulnerability creates opportunities for attackers to escalate privileges and gain unauthorized access to additional resources within the SharePoint environment.
Operationally, this flaw significantly impacts organizations relying on SharePoint for document management and collaboration services. An attacker exploiting this vulnerability can conduct man-in-the-middle attacks, session hijacking, or credential replay attacks that compromise user identities and potentially lead to complete system infiltration. The spoofing capability allows malicious actors to impersonate legitimate users and perform unauthorized operations within the SharePoint platform, including accessing sensitive documents, modifying content, or executing administrative functions. This threat vector particularly affects organizations where SharePoint serves as a central hub for business-critical information.
Organizations should implement comprehensive mitigation strategies including mandatory use of secure communication protocols such as tls 1.3, implementation of multi-factor authentication, regular credential rotation policies, and enhanced network monitoring to detect suspicious activities. Security controls should focus on strengthening transport layer security through proper certificate management and ensuring that all authentication mechanisms utilize strong cryptographic standards. Additionally, organizations must conduct regular security assessments and penetration testing to identify potential credential exposure vulnerabilities. The mitigation approach should align with industry best practices outlined in frameworks such as nist cybersecurity framework and mitre att&ck matrix category ta0006 credential access, which specifically addresses techniques for acquiring credentials through network interception and authentication manipulation.
Organizations must also implement proper network segmentation strategies to limit the scope of potential attacks and reduce the attack surface available to malicious actors. Regular security awareness training for administrators and users can help prevent initial compromise through social engineering or misconfigurations that may exacerbate this vulnerability. The implementation of robust logging and monitoring solutions enables early detection of credential abuse attempts and provides essential forensic data for incident response activities.