https://patchthecve.com/CVEs with upgrade or downgrade fix stepshttps://patchthecve.com/cve/CVE-2021-20230.htmlhttps://patchthecve.com/cve/CVE-2021-20230.htmlWed, 17 Jun 2026 03:33:30 +0000HIGH 7.5: 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 achttps://patchthecve.com/cve/CVE-2015-3644.htmlhttps://patchthecve.com/cve/CVE-2015-3644.htmlWed, 17 Jun 2026 00:26:02 +0000MEDIUM 5.8: Stunnel 5.00 through 5.13, when using the redirect option, does not redirect client connections to the expected server after the initial connection, which allows remote attackers to bypass authentication.https://patchthecve.com/cve/CVE-2014-0016.htmlhttps://patchthecve.com/cve/CVE-2014-0016.htmlWed, 17 Jun 2026 00:02:05 +0000MEDIUM 4.3: stunnel before 5.00, when using fork threading, does not properly update the state of the OpenSSL pseudo-random number generator (PRNG), which causes subsequent children with the same process ID to use the same entropy pool and allows remote attackers to obtain private keys for EC (ECDSA) or DSA cerhttps://patchthecve.com/cve/CVE-2013-1762.htmlhttps://patchthecve.com/cve/CVE-2013-1762.htmlTue, 16 Jun 2026 23:52:04 +0000MEDIUM 6.6: stunnel 4.21 through 4.54, when CONNECT protocol negotiation and NTLM authentication are enabled, does not correctly perform integer conversion, which allows remote proxy servers to execute arbitrary code via a crafted request that triggers a buffer overflow.https://patchthecve.com/cve/CVE-2011-2940.htmlhttps://patchthecve.com/cve/CVE-2011-2940.htmlTue, 16 Jun 2026 23:32:17 +0000HIGH 9.3: stunnel 4.40 and 4.41 might allow remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) via unspecified vectors.