CVE-2021-20230

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.

Category

7.5
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.23%
Vendor Advisory gentoo.org
Affected: n/a stunnel
Published at:
Updated at:

References

Link Tags
https://bugzilla.redhat.com/show_bug.cgi?id=1925226 issue tracking third party advisory
https://github.com/mtrojnar/stunnel/commit/ebad9ddc4efb2635f37174c9d800d06206f1edf9 patch third party advisory
https://security.gentoo.org/glsa/202105-02 vendor advisory third party advisory

Frequently Asked Questions

What is the severity of CVE-2021-20230?
CVE-2021-20230 has been scored as a high severity vulnerability.
How to fix CVE-2021-20230?
To fix CVE-2021-20230, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-20230 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-20230 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-20230?
CVE-2021-20230 affects n/a stunnel.
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