https://vulnerability.circl.lu/rss/recent/all/10 Most recent entries from all 2026-10-01T12:36:37.583433+00:00 Vulnerability-Lookup info@circl.lu python-feedgen Contains only the most 10 recent entries. https://vulnerability.circl.lu/vuln/cve-2021-20230 CVE-2021-20230 2026-10-01T12:36:37.606297+00:00

Affected: stunnel

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.

 https://vulnerability.circl.lu/vuln/usn-6901-1 USN-6901-1 — stunnel4 vulnerability 2026-10-01T12:36:37.606625+00:00

Affected: Ubuntu:Pro:18.04:LTS: stunnel4, Ubuntu:20.04:LTS: stunnel4

It was discovered that stunnel did not properly validate client certificates when configured to use both the redirect and verifyChain options. A remote attacker could potentially use this issue to obtain sensitive information by accessing the tunneled service.