Description of the security update for the information disclosure vulnerability in Visual Studio 2015 Update 3: April 10, 2018

Applies to: All Visual Studio 2015 Update 3 editions except Isolated and Integrated Shells 


In November 2020, the content of this article was updated to clarify the affected products, prerequisites, and restart requirements. Additionally, the update metadata in WSUS was revised to fix a Microsoft System Center Configuration Manager reporting bug.

An information disclosure vulnerability exists if Visual Studio incorrectly discloses limited contents of uninitialized memory while compiling program database (PDB) files. An attacker who exploits the vulnerability could view uninitialized memory from the computer that is used to compile a program database file.

To learn more about the vulnerability, see CVE-2018-1037.

The following file is available for download:

Download Download the hotfix package now.

To get the standalone package for this update, go to the Microsoft Update Catalog website.

To apply this security update, you must have both Visual Studio 2015 Update 3 and the subsequent Cumulative Servicing Release KB 3165756 installed. Typically, KB 3165756 is installed automatically when you install Visual Studio 2015 Update 3. However, in some cases, you have to install the two packages separately.

We recommend that you close Visual Studio 2015 before you install this security update. Otherwise, you may have to restart the computer after you apply this security update if a file that is being updated is open or in use by Visual Studio.

This security update doesn't replace other security updates.

This security update addresses the PDB issue that is described in CVE-2018-1037, in which a PDB file may contain uninitialized heap content in a process that updates an existing PDB file, such as Mspdbsrv.exe. We strongly recommend that you use the updated PDBCopy tool to check every existing PDB that you intend to share or distribute.

If you're using the /DEBUG:fastlink linker option to build your projects or solutions and you're using Mspdbcmf.exe to convert linker-generated fastlink PDB files into full PDB files, the resulting full PDB files could also have this information-disclosure vulnerability. To obtain an update to Visual Studio 2015 Mspdbcmf.exe, go to this Knowledge Base article.

If you also use Visual Studio 2017, you can use the Mspdbcmf.exe file that is included in the latest Visual Studio 2017 preview or update to convert fastlink PDB files that are generated by the Visual Studio 2015 linker. (PDBs that are generated by the latest Visual Studio 2017 Mspdbcmf.exe file are not vulnerable.)

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To verify that this security update is applied correctly, follow these steps:

  1. Open the Visual Studio 2015 program folder.

  2. Locate the Mspdbcore.dll file.

  3. Verify that the file version is equal to or greater than 14.0.24235.

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