Vulnerability Name:

CVE-2021-3547 (CCN-205343)

Assigned:2021-07-09
Published:2021-07-09
Updated:2022-10-27
Summary:OpenVPN 3 Core Library version 3.6 and 3.6.1 allows a man-in-the-middle attacker to bypass the certificate authentication by issuing an unrelated server certificate using the same hostname found in the verify-x509-name option in a client configuration.
CVSS v3 Severity:7.4 High (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N)
6.4 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): High
Availibility (A): None
6.8 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N)
5.9 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): None
User Interaction (UI): Required
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): High
Availibility (A): None
CVSS v2 Severity:5.8 Medium (CVSS v2 Vector: AV:N/AC:M/Au:N/C:P/I:P/A:N)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Medium
Authentication (Au): None
Impact Metrics:Confidentiality (C): Partial
Integrity (I): Partial
Availibility (A): None
6.6 Medium (CCN CVSS v2 Vector: AV:N/AC:H/Au:S/C:C/I:C/A:N)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): High
Athentication (Au): Single_Instance
Impact Metrics:Confidentiality (C): Complete
Integrity (I): Complete
Availibility (A): None
Vulnerability Type:CWE-295
Vulnerability Consequences:Obtain Information
References:Source: MITRE
Type: CNA
CVE-2021-3547

Source: MISC
Type: Patch, Vendor Advisory
https://community.openvpn.net/openvpn/wiki/CVE-2021-3547

Source: CCN
Type: OpenVPN Web site
CVE-2021-3547: OpenVPN 3 Core library 3.6 and 3.6.1 possible certificate authentication bypass with --verify-x509-name

Source: MISC
Type: Vendor Advisory
https://community.openvpn.net/openvpn/wiki/SecurityAnnouncements

Source: XF
Type: UNKNOWN
openvpn-cve20213547-mitm(205343)

Vulnerable Configuration:Configuration 1:
  • cpe:/a:openvpn:openvpn:3.6:*:*:*:*:*:*:*
  • OR cpe:/a:openvpn:openvpn:3.6.1:*:*:*:*:*:*:*

    • * Denotes that component is vulnerable
    BACK
    openvpn openvpn 3.6
    openvpn openvpn 3.6.1