If your company uses Microsoft 365 Copilot, you should be aware of a new security issue called SearchLeak. Until recently, an attacker could steal your 2FA codes, emails, and important documents – all with just a single click on a link that appeared to come from Microsoft.
Researchers at Varonis Threat Labs discovered this vulnerability in Microsoft 365 Copilot’s Enterprise Search and named it “SearchLeak.” Microsoft assigned a “Critical” rating (CVE-2026-42824) to the flaw and has since patched it. Nevertheless, the way this exploit functioned serves as a major warning for anyone using AI tools with business data. It is a reminder that these tools are not merely “smart”—they are also systems that require constant monitoring.
How the Attack Worked
SearchLeak wasn’t just a simple bug; turning Copilot’s search function into a secret data tunnel for an attacker required three specific steps.
The attacker manipulated a URL, specifically tampering with Copilot’s “q” search parameter. Instead of a standard search query, they injected instructions that compelled Copilot to scan the victim’s mailbox and transmit any findings to an attacker-controlled server. The link appeared innocuous—originating directly from microsoft.com, so phishing filters raised no alarms.
Microsoft had implemented safeguards; in theory, Copilot’s responses are wrapped in a sanitized code block. However, if an img tag is surreptitiously injected into the AI’s response, it triggers before the sanitizer can block it. That tiny window of opportunity is all it takes for data to be exfiltrated.
Bing’s image search endpoint is on Microsoft’s allowlist. Consequently, the attacker exfiltrates the stolen data via Bing’s own servers. The traffic appears entirely legitimate, as if originating from within Microsoft, leaving monitoring tools none the wiser.
The victim sees nothing unusual. Copilot appears to think for a moment. The data is already gone.
What Was at Risk
If an attacker breaches your account, they could gain access to:
- Real-time 2FA and MFA codes directly from your email inbox
- Everything in your email, such as subject lines, messages, and attachments
- Password reset links and one-time codes
- Calendar details, including meetings, attendees, and any private notes
- Sensitive files that Copilot can scan, such as financial reports, salary information, and merger and acquisition plans saved in SharePoint or OneDrive
What Wichita Business Owners Should Do Right Now
Microsoft patched the SearchLeak vulnerability back in June 2026. You do not need to perform any updates yourself. However, this entire incident highlights a major issue: every AI tool connected to your company’s data represents a potential new entry point for attackers, and frankly, most companies are operating without full visibility.
Practical steps to take this week:
- First, audit exactly who has access to Microsoft 365 Copilot. Check if it is linked to sensitive SharePoint sites or inboxes; if so, reconsider who truly requires that level of access.
- Second, stop relying on email for 2FA codes on critical systems. Switch to using an authenticator app instead, as attackers frequently intercept email-based codes.
- Next, review Copilot’s data permissions. Since it can only leak data it has visibility into, carefully determine which data it is allowed to index.
- After that, conduct a security review of every AI tool used in your business, whether it’s Copilot, ChatGPT plugins, third-party integrations, or anything classified as an “AI assistant.”
- Finally, ensure your incident response plan is ready. If someone accessed your data prior to the patch, you need to know how to detect it and what actions to take in response.
The SearchLeak issue has been resolved, but you can assume that someone is already working on the next exploit targeting AI tools. The real question is whether you will discover it before or after your data has been compromised.
We’re Based in Wichita. We Know What You’re Up Against.
Threats like SearchLeak aren’t just a problem for large corporations. They target Wichita law firms, medical clinics, manufacturers, and even local banks; in fact, any business that uses Microsoft 365 can fall victim. Often, employees don’t even realize something is wrong.
Having worked with Wichita businesses for over 21 years, we understand that most local companies don’t have a dedicated IT security team. This isn’t a shortcoming; it’s simply the nature of doing business here. And attackers are constantly looking for exactly that kind of opportunity.
Most businesses in Wichita have no idea just how vulnerable they are. It’s not that they’re careless; it’s simply that the game has changed, and security practices haven’t kept pace. Tools like Copilot? They’re fantastic, but only if you set them up correctly. Otherwise, you’re just inviting trouble.
We live and work right here in Wichita. We aren’t some faceless national company that sends someone over when a major crisis hits. We understand the local market and your specific challenges, and we can give you a clear assessment of your situation in just half an hour, no fluff, no nonsense.
Talk to engineers who understand your business
Ransom Security has been helping Wichita businesses stay secure for more than 21 years. We get how risky AI tools can be in the workplace, and we know how to fix those gaps before attackers spot them.
Need someone to take a close look at your Microsoft 365 setup? Or maybe you just want a quick, honest chat about your company’s security? Give us a call, or try our free assessment.
If you’re in the middle of an incident, maybe you’ve noticed strange account activity, someone got in who shouldn’t have, or your Copilot is acting up, don’t wait. Reach out right away. That first hour makes all the difference.