Visual Studio Copilot / SSMS CVE-2026-103572: trailing-dot path bypass lets the agent rewrite its own settings and escape containment for command execution, including via indirect prompt injection; Microsoft Important RCE patch shipped 13 Oct
Security researcher wunderwussi (Embrace The Red) published on 13 October 2026 that Microsoft patched CVE-2026-103572, an Important-severity remote code execution issue in the shared Microsoft.VisualStudio.Copilot.Core.dll used by GitHub Copilot in Visual Studio (including Visual Studio 2026 and older Visual Studio 2022 trains) and SQL Server Management Studio. A path-validation check that was meant to block writes to sensitive Copilot settings and MCP configuration files could be bypassed by appending a trailing ASCII period to the filename: Win32 APIs strip the final dot, so a write to settings.json. or .mcp.json. lands on the protected file. That lets the agent escape containment and run arbitrary commands; the report also shows a third party can drive the same outcome through indirect prompt injection. Microsoft classified the issue as Important RCE and shipped the fix with the 13 October updates. Operators who enable Copilot inside Visual Studio or SSMS should apply the October Visual Studio / SSMS Copilot updates promptly and treat untrusted repo content as able to steer agent file writes until patched.
- Product
- GitHub Copilot in Visual Studio and SQL Server Management Studio (Microsoft.VisualStudio.Copilot.Core.dll)
- Versions
- Affected: Copilot integration in Visual Studio (including VS 2026 and older VS 2022) and SSMS sharing the vulnerable Copilot Core DLL before the 13 Oct 2026 patch. Fixed: October 2026 Visual Studio / SSMS Copilot updates per MSRC CVE-2026-103572.
- Exploited in Australia?
- unknown
- Patch to
- Apply the 13 October 2026 Visual Studio and SSMS Copilot updates that address CVE-2026-103572. Until patched, limit Copilot agent file-edit rights on untrusted repositories and treat trailing-dot filenames as a bypass of settings/MCP write guards.
Primary: Embrace The Red — Visual Studio Copilot and SSMS Remote Code Execution (CVE-2026-103572, 13 Oct 2026) · Vendor: Microsoft Security Update Guide — CVE-2026-103572 · CVE: CVE-2026-103572 · Talkback.sh resources listing pointing to the Embrace The Red write-up