Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Stunnel | Stunnel | < 5.57 |
Related Weaknesses (CWE)
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1925226Issue TrackingThird Party Advisory
- https://github.com/mtrojnar/stunnel/commit/ebad9ddc4efb2635f37174c9d800d06206f1ePatchThird Party Advisory
- https://security.gentoo.org/glsa/202105-02Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1925226Issue TrackingThird Party Advisory
- https://github.com/mtrojnar/stunnel/commit/ebad9ddc4efb2635f37174c9d800d06206f1ePatchThird Party Advisory
- https://security.gentoo.org/glsa/202105-02Third Party Advisory
FAQ
What is CVE-2021-20230?
CVE-2021-20230 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 certi...
How severe is CVE-2021-20230?
CVE-2021-20230 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-20230?
Check the references section above for vendor advisories and patch information. Affected products include: Stunnel Stunnel.