CVE-2021-20230
Fixed in a distro release EPSS 1%
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.
Products: stunnel
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| AlmaLinux 8 | stunnel | 5.56-5.el8_3 |
| Debian 12 | stunnel4 | 3:5.56+dfsg-8 |
| Debian 13 | stunnel4 | 3:5.56+dfsg-8 |
| Red Hat Enterprise Linux 8 | stunnel | 0:5.56-5.el8_3 |
| Red Hat Enterprise Linux 8 | stunnel-debuginfo | 0:5.56-5.el8_3 |
| Red Hat Enterprise Linux 8 | stunnel-debugsource | 0:5.56-5.el8_3 |
| Red Hat rhel eus 8.1 | stunnel | 0:5.48-6.el8_1 |
| Red Hat rhel eus 8.1 | stunnel-debuginfo | 0:5.48-6.el8_1 |
| Red Hat rhel eus 8.1 | stunnel-debugsource | 0:5.48-6.el8_1 |
| Red Hat rhel eus 8.2 | stunnel | 0:5.48-6.el8_2 |
| Red Hat rhel eus 8.2 | stunnel-debuginfo | 0:5.48-6.el8_2 |
| Red Hat rhel eus 8.2 | stunnel-debugsource | 0:5.48-6.el8_2 |
| Rocky Linux 8 | stunnel | 0:5.56-5.el8_3 |
| SUSE Enterprise Storage 6 | stunnel | 5.44-3.8.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS | stunnel | 5.44-3.8.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS | stunnel | 5.44-3.8.1 |
| SUSE Linux Enterprise High Performance Computing 15-ESPOS | stunnel | 5.44-3.8.1 |
| SUSE Linux Enterprise High Performance Computing 15-LTSS | stunnel | 5.44-3.8.1 |
| SUSE Linux Enterprise Module for Server Applications 15 SP2 | stunnel | 5.57-3.11.1 |
| SUSE Linux Enterprise Server 15 SP1-BCL | stunnel | 5.44-3.8.1 |
| SUSE Linux Enterprise Server 15 SP1-LTSS | stunnel | 5.44-3.8.1 |
| SUSE Linux Enterprise Server 15-LTSS | stunnel | 5.44-3.8.1 |
| SUSE Linux Enterprise Server for SAP Applications 15 | stunnel | 5.44-3.8.1 |
| SUSE Linux Enterprise Server for SAP Applications 15 SP1 | stunnel | 5.44-3.8.1 |
| SUSE Manager Proxy 4.0 | stunnel | 5.44-3.8.1 |
| SUSE Manager Retail Branch Server 4.0 | stunnel | 5.44-3.8.1 |
| SUSE Manager Server 4.0 | stunnel | 5.44-3.8.1 |
| Ubuntu 20.04 LTS | stunnel4 | 3:5.56-1ubuntu0.2 |
| Ubuntu Pro 18.04 LTS | stunnel4 | 3:5.44-1ubuntu3+esm1 |
| openSUSE Leap 15.2 | stunnel | 5.57-lp152.2.6.1 |