VULNERABILITY INTELLIGENCE

CVE-2021-20230

CVSS score7.5 HIGH
EPSS probability1.18%
CISA KEVNot currently listed
Published2021-02-23
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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.

Weakness classification

  • secalert@redhat.com: CWE-295

Primary references