CVE-2018-20840

An unhandled exception vulnerability exists during Google Sign-In with Google API C++ Client before 2019-04-10. It potentially causes an outage of third-party services that were not designed to recover from exceptions. On the client, ID token handling can cause an unhandled exception because of misinterpretation of an integer as a string, resulting in denial-of-service and then other users can no longer login/sign-in to the affected third-party service. Once this third-party service uses Google Sign-In with google-api-cpp-client, a malicious user can trigger this client/auth/oauth2_authorization.cc vulnerability by requesting the client to receive the ID token from a Google authentication server.

• CVE ID
• CVE-2018-20840

• Assigner
• cve@mitre.org

• Vulnerability Status
• Analyzed

• Published Version
• 2019-05-30T16:29:01

• Last Modified Date
• 2019-05-31T16:04:32

• Version
• 2.0

• Vector String
• AV:N/AC:L/Au:N/C:N/I:N/A:P

• Access Vector
• NETWORK

• Access Compatibility
• LOW

• Authentication
• NONE

• Confidentiality Impact
• NONE

• Integrity Impact
• NONE

• Availability Impact
• PARTIAL

• Base Score
• 5

• Severity
• MEDIUM

• Exploitability Score
• 10

• Impact Score
• 2.9

• Version
• 3.0

• Vector String
• CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

• Attack Vector
• NETWORK

• Attack Compatibility
• LOW

• Privileges Required
• NONE

• User Interaction
• NONE

• Scope
• CHANGED

• Confidentiality Impact
• NONE

• Availability Impact
• HIGH

• Base Score
• 8.6

• Base Severity
• HIGH

• Exploitability Score
• 3.9

• Impact Score
• 4