SearchLeak exposes Microsoft 365 Copilot data
Varonis Threat Labs discovered 'SearchLeak,' a critical one-click vulnerability chain in Microsoft 365 Copilot tracked under CVE-2026-42824. The exploit chains a Parameter-to-Prompt injection with a browser rendering race condition and a Bing SSRF bypass to silently exfiltrate organizational data.
Combining LLMs with direct graph access and untrusted URL inputs creates an inherently insecure attack surface that elevates classic web bugs into critical enterprise-wide compromise vectors.
* Parameter-to-Prompt (P2P) injection turns a natural language search query parameter into a silent, auto-executed instruction set.
* Incremental DOM rendering during streaming allows malicious HTML image tags to execute and fire HTTP requests before Copilot's post-processing output sanitizer wraps the response.
* Allowed CSP domains like Bing can be abused as exfiltration proxies by triggering their server-side request forgery (SSRF) endpoints.
* Since Copilot inherits the victim's full graph permissions, attackers can silently access MFA codes, emails, calendars, and private company files with zero additional verification.
DISCOVERED
2h ago
2026-06-15
PUBLISHED
3h ago
2026-06-15
RELEVANCE
AUTHOR
IntCyberDigest