Installers of Mozilla Firefox and Thunderbird for Windows may insecurely load Dynamic Link Libraries


Installers of Mozilla Firefox and Thunderbird for Windows provided by Mozilla Foundation contain an issue with the DLL search path, which may lead to insecurely loading Dynamic Link Libraries (CWE-427).

Eili Masami of Tachibana Lab. 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

mozilla.org contributors
  • Mozilla Firefox prior to version 54
  • Mozilla Firefox ESR prior to version 52.2
  • Mozilla Thunderbird prior to version 52.2


Arbitrary code may be executed with the privilege of the user invoking the installer.

[Use the Latest Installer]
Use the latest installer according to the information provided by the developer.
Users who already have installed Mozilla Firefox or Thunderbird do not need to re-install the application, because this issue affects the installer only.
Vendor Information

mozilla.org contributors
CWE (What is CWE?)

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

  1. CVE-2017-7755

  1. JVN : JVN#81676004
  2. JVN : JVNTA#91240916
  3. National Vulnerability Database (NVD) : CVE-2017-7755
Revision History

  • [2017/07/11]
      Web page was published
  • [2018/08/30]
      References : Contents were added