SearchLeak is a three-stage attack chain targeting Microsoft 365 Copilot Enterprise. It begins with a parameter-to-prompt injection via the 'q' URL parameter, instructing Copilot to search the victim's mailbox or other data sources and format the results in an image URL. Next, an HTML rendering race condition allows attacker-controlled HTML with an <img> tag to execute before sanitization completes. Finally, an SSRF vulnerability in Bing's 'Search by Image' feature causes Bing to fetch the attacker's URL containing the stolen data, bypassing content security policy protections. This chain enables data exfiltration through a single click on a malicious link. Microsoft assigned CVE-2026-42824 to this vulnerability and released a fix at the beginning of June 2026.

Successful exploitation results in unauthorized exfiltration of sensitive enterprise data including email content (such as access codes and passwords), calendar events, meeting details, documents, and other information accessible via Microsoft 365 Copilot Enterprise Search. The victim is unaware of the data theft as the attack appears as normal Copilot activity. This poses a critical risk to confidentiality of corporate data.

Microsoft has released an official fix for CVE-2026-42824 addressing the SearchLeak vulnerability. No user action is required to mitigate this threat as the patch has been applied by Microsoft. Organizations should verify that their Microsoft 365 Copilot Enterprise environment is updated according to Microsoft's guidance.