Description

Improper input validation in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.6",
  "pubDate": "2026-08-11T17:18:45.700Z",
  "pubdate": "2026-08-11T17:18:45.700Z",
  "executiveSummary": "This security analysis evaluates an improper input validation vulnerability affecting Microsoft Office SharePoint.\nThe vulnerability is classified as an input validation flaw that enables an authorized remote attacker to conduct spoofing attacks across a network.\nThe primary impact of successful exploitation includes the manipulation of user perception or interface integrity, potentially misleading users into interacting with fraudulent content or malicious components disguised as legitimate SharePoint elements.\nThe affected product is Microsoft Office SharePoint.\nRisk implications center around the degradation of trust within the collaboration platform, potential credential harvesting vectors, and unauthorized data exposure through deceptive interface rendering.\nAttacker capabilities require authorization within the targeted environment, meaning the adversary must possess valid credentials or an established session to interact with the vulnerable application functions.\nExploitation requirements necessitate network access to the target SharePoint instance and the ability to submit or supply maliciously crafted input that bypasses validation routines, resulting in unauthorized spoofing behaviors over the network.",
  "technicalDetails": "The root cause of this vulnerability lies in the insufficient validation and sanitization of user-supplied input handled by Microsoft Office SharePoint.\nThe vulnerable component processes parameters or payloads that are subsequently reflected or rendered within the application interface without proper contextual output encoding or rigorous structural verification.\nBecause the application fails to adequately inspect input for semantic and syntactic correctness, an authorized attacker can inject specially crafted strings or structural elements that alter how information is presented to other users.\nRegarding authentication and privilege requirements, the threat actor must be authorized, implying that anonymous network access is insufficient; the adversary must authenticate to the SharePoint environment to deliver the malicious payload.\nNetwork exposure is explicitly documented, as the attack is executed remotely over a network connection targeting the web-facing services of Microsoft Office SharePoint.\nThe step-by-step attack flow proceeds as follows: First, the authorized attacker crafts a malicious input payload designed to exploit the lack of strict input validation within a specific SharePoint endpoint or function. Second, the attacker transmits this payload across the network to the target SharePoint server using standard protocols. Third, the vulnerable component processes the input, storing or reflecting it without proper sanitization. Fourth, when a victim user accesses the affected SharePoint resource, the unsanitized input is rendered by the application context. Fifth, the malicious payload executes or displays misleading visual data, achieving the spoofing objective by masquerading as trusted application output.\nThe payload behavior focuses on visual deception, interface manipulation, or content spoofing rather than direct remote code execution.\nPost-exploitation impact involves the potential erosion of user trust, facilitation of secondary social engineering attacks within the SharePoint domain, and potential unauthorized interaction with sensitive resources based on deceptive application states."
}