msrc-blog

Cross-Site Scripting (XSS) has been a known vulnerability class for two decades, yet it continues to surface in modern applications, including those built with the latest frameworks and cloud-native architectures. At Microsoft, we still receive a steady stream of XSS reports across our services, from legacy portals to newly deployed single-page apps.

The next chapter of the Microsoft Security Response Center’s (MSRC) BlueHat security conference is fast approaching. BlueHat Asia 2025 will take place in Bengaluru, India, on November 5 – 6, 2025 and the Call for Papers is now open. Submissions will be accepted through September 5, 2025. Now in its third decade, BlueHat is more than a conference, it’s a community.

The next chapter of the Microsoft Security Response Center’s (MSRC) BlueHat security conference is fast approaching. BlueHat Asia 2025 will take place in Bengaluru, India, on November 5 – 6, 2025 and the Call for Papers is now open. Submissions will be accepted through September 14, 2025. Now in its third decade, BlueHat is more than a conference, it’s a community.

At Microsoft, securing the ecosystem means more than just fixing bugs—it means proactively hunting for variant classes, identifying systemic weaknesses, and working across teams to protect customers before attackers ever get the chance. This blog highlights one such effort: a deep dive into the risks of misconfigured postMessage handlers across Microsoft services and how MSRC worked with engineering teams to mitigate them.

We’re thrilled to share that this year, the Microsoft Bounty Program has distributed $17 million to 344 security researchers from 59 countries, the highest total bounty awarded in the program’s history. In close collaboration with the Microsoft Security Response Center (MSRC), these security researchers have helped identify and resolve more than a thousand potential vulnerabilities, strengthening protections for Microsoft customers around the world.

Last year, we announced the largest hacking event in history: Zero Day Quest, with up to $4 million in bounty awards. The response from the global security community was incredible and helped improve security for our customers and partners. This year, Zero Day Quest is back with even more potential bounty awards: up to $5 million total for high-impact research in Cloud and AI security.

We’re excited to announce significant updates to the Microsoft .NET Bounty Program. These changes expand the program’s scope, simplify the award structure, and offer great incentives for security researchers. The .NET Bounty Program now offers awards up to $40,000 USD for vulnerabilities impacting the .NET and ASP.NET Core (including Blazor and Aspire).

We’re excited to announce significant updates to the Microsoft .NET Bounty Program. These changes expand the program’s scope, simplify the award structure, and offer great incentives for security researchers. The .NET Bounty Program now offers awards up to $40,000 USD for vulnerabilities impacting the .NET and ASP.NET Core (including Blazor and Aspire).

Summary The growing adoption of large language models (LLMs) in enterprise workflows has introduced a new class of adversarial techniques: indirect prompt injection. Indirect prompt injection can be used against systems that leverage large language models (LLMs) to process untrusted data. Fundamentally, the risk is that an attacker could provide specially crafted data that the LLM misinterprets as instructions.

Summary Microsoft is aware of active attacks targeting on-premises SharePoint Server customers. The attacks are exploiting a variant of CVE-2025-49706. This vulnerability has been assigned CVE-2025-53770. SharePoint Online in Microsoft 365 is not impacted. A patch is currently not available for this vulnerability. Mitigations and detections are provided below.