Windows 7 may insecurely load Dynamic Link Libraries


In standard DLL files provided by Windows 7, there are some DLL files read from the same directory where the program resides when executing the program (CWE-427).

Microsoft states that the root cause of this vulnerability is "Application Directory (App Dir) DLL planting", thus there is no plan to release any security updates for Windows 7 to address this issue.

For details, refer to "Application Directory (App Dir) DLL planting" released by Microsoft.

Takashi Yoshikawa of Mitsui Bussan Secure Directions, Inc. reported this vulnerability to IPA.
JPCERT/CC coordinated with the developer under Information Security Early Warning Partnership.
CVSS Severity (What is CVSS?)

CVSS V3 Severity:
Base Metrics 7.8 (High) [IPA Score]
  • Attack Vector: Local
  • Attack Complexity: Low
  • Privileges Required: None
  • User Interaction: Required
  • Scope: Unchanged
  • Confidentiality Impact: High
  • Integrity Impact: High
  • Availability Impact: High
CVSS V2 Severity:
Base Metrics 6.8 (Medium) [IPA Score]
  • Access Vector: Network
  • Access Complexity: Medium
  • Authentication: None
  • Confidentiality Impact: Partial
  • Integrity Impact: Partial
  • Availability Impact: Partial
Affected Products

Microsoft Corporation
  • Microsoft Windows 7


If a specially crafted DLL file is located in the same directory as executable file, arbitrary code may be executed.

[Upgrade to Windows 10]
Upgrade to the latest Windows 10 from Windows 7 according to the information provided by the developer.

[Apply Workaround]
Applying the following workarounds may mitigate the impacts of this vulnerability.

*Restrict the permission to write system directories only to an administrator, which is the Windows' initial configuration.
*Operate an Windows PC with a standard user (non-administrator) account. An administrator account should be used only when necessary.
*Make sure there are no untrusted files in the directory where the application is installed.
*If your organization uses shared directories to place applications for organizational operations, make sure that the shared directory is set read-only for non-administrative users.
Vendor Information

Microsoft Corporation
CWE (What is CWE?)

  1. No Mapping(CWE-Other) [IPA Evaluation]
CVE (What is CVE?)

  1. CVE-2019-5921

  1. JVN : JVNTA#91240916
  2. JVN : JVN#69181574
  3. National Vulnerability Database (NVD) : CVE-2019-5921
Revision History

  • [2019/02/28]
      Web page was published
  • [2019/09/26]
      References : Content was added