CVE-2025-21393 is a spoofing vulnerability identified in Microsoft SharePoint Server. The vulnerability has been assigned a CVSS score of 6.3, categorizing it as medium severity. This classification is crucial as it indicates the potential risk to organizations that utilize SharePoint Server in their operations.
Risk to organizations includes unauthorized access to sensitive information, due to the high confidentiality impact associated with this vulnerability. The exploitation status is currently unconfirmed, but the absence of known exploits highlights an urgency for defenders to address this vulnerability promptly.
Organizations should prioritize patching immediately to prevent potential exploitation. The relevant updates and patches can be obtained from official Microsoft sources.
As of now, the vulnerability remains unlisted in the Known Exploited Vulnerabilities (KEV) catalog, indicating there have been no confirmed active exploitation cases reported.
Vulnerability Details
The Microsoft SharePoint Server Spoofing Vulnerability allows attackers to potentially spoof user identities. The official CVE description highlights the nature of this vulnerability, which is classified under CWE-79, indicating an issue related to improper input validation.
The CVSS score of 6.3 reflects a medium severity which indicates a moderate level of risk. This has been derived from a combination of factors including a network attack vector, low attack complexity, and required user interaction.
The affected products include SharePoint Server 2016 and 2019, as well as certain subscription versions. Organizations using these versions should ensure they are aware of the implications of this vulnerability.
Technical Analysis
The root cause of CVE-2025-21393 lies in the insufficient validation of user input in SharePoint Server. Attackers may leverage this weakness by sending specially crafted requests to the server, which could lead to user identity spoofing.
The attack vector is network-based, meaning that an attacker could exploit this vulnerability remotely without physical access to the server. The attack complexity is classified as low, indicating that the steps to exploit this vulnerability are straightforward, although user interaction is required.
With low privileges required for exploitation, it is possible for an attacker with limited access to initiate an attack. The confidentiality impact is high, while the integrity impact is low, and there is no availability impact associated with this vulnerability.
Risk & Impact Analysis
Real-world deployment risk for CVE-2025-21393 is significant due to the potential for unauthorized access to sensitive data. Organizations that rely on SharePoint Server for collaboration and data storage may face serious confidentiality breaches if this vulnerability is exploited.
This matters to organizations because the impact of a successful exploit could include data breaches, loss of sensitive information, and damage to reputation. The blast radius potential is considerable, especially in environments where SharePoint Server is widely used across different departments.
Given the current CVSS score and lack of known exploitation, organizations should schedule remediation and address this vulnerability in their patch management cycle.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerability affects Microsoft SharePoint Server 2016 and 2019, as well as subscription versions prior to 16.0.17928.20356. Organizations should ensure their systems are updated to the latest versions to mitigate risks.
Mitigation & Remediation
Organizations should prioritize patching by applying the latest updates from Microsoft. If a patch is unavailable, consider implementing workarounds, such as restricting access to vulnerable components and enhancing monitoring of user activities.
For further guidance on the patching process, organizations may refer to penetration testing services to validate remediation efforts.
Detection Guidance
Organizations should monitor logs for unusual access patterns, particularly around authentication processes. Behavioral anomalies, such as unexpected changes in user roles or permissions, should also be investigated.
Network signatures associated with SharePoint should be analyzed to identify potential spoofing attempts. It is critical to keep systems updated and to regularly review user access rights.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2025-21393 lies in its implications for organizations that heavily utilize SharePoint for collaboration. As spoofing vulnerabilities can lead to unauthorized access, it is essential for security teams to implement robust security measures.
This vulnerability represents a potential trend in the exploitation of user identity validation flaws. Organizations should learn from this case to enhance their security posture against similar vulnerabilities in the future.
A strategic defensive takeaway is to incorporate regular security assessments, such as application security assessments, to identify weaknesses before they can be exploited.
Furthermore, organizations should stay informed about emerging threats and trends in vulnerability exploitation, allowing for proactive adjustments to their security strategies.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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