CVE-2021-20230

Severity CVSS v4.0:

Pending analysis

Type:

CWE-295 Improper Certificate Validation

Publication date:

23/02/2021

Last modified:

01/06/2022

Description

A flaw was found in stunnel before 5.57, where it improperly validates client certificates when it is configured to use both redirect and verifyChain options. This flaw allows an attacker with a certificate signed by a Certificate Authority, which is not the one accepted by the stunnel server, to access the tunneled service instead of being redirected to the address specified in the redirect option. The highest threat from this vulnerability is to confidentiality.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N CVSS v3.1 Severity and Metrics:

Base Score: 7.50 HIGH
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): None
Availability (A): None

Base Score 3.x

7.50

Severity 3.x

HIGH

Vector 2.0

AV:N/AC:L/Au:N/C:P/I:N/A:N CVSS v2.0 Severity and Metrics:

Base Score: 5.00 MEDIUM
Vector: AV:N/AC:L/Au:N/C:P/I:N/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Authentication (Au): None
Confidentiality (C): Physical
Integrity (I): None
Availability (A): None