vulnerability
Red Hat: CVE-2021-20230: CVE-2021-20230 stunnel: client certificate not correctly verified when redirect and verifyChain options are used (Multiple Advisories)
| Severity | CVSS | Published | Added | Modified |
|---|---|---|---|---|
| 5 | (AV:N/AC:L/Au:N/C:P/I:N/A:N) | Feb 22, 2021 | Feb 23, 2021 | Aug 11, 2025 |
Severity
5
CVSS
(AV:N/AC:L/Au:N/C:P/I:N/A:N)
Published
Feb 22, 2021
Added
Feb 23, 2021
Modified
Aug 11, 2025
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.
Solutions
redhat-upgrade-stunnelredhat-upgrade-stunnel-debuginforedhat-upgrade-stunnel-debugsource
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