CVE-2022-3786

Name of the Vulnerable Software and Affected Versions OpenSSL versions 3.0.0 through 3.0.6

Description A buffer overrun can be triggered in X.509 certificate verification, specifically in name constraint checking. This occurs after certificate chain signature verification and requires either a CA to have signed a malicious certificate or for an application to continue certificate verification despite failure to construct a path to a trusted issuer. An attacker can craft a malicious email address in a certificate to overflow an arbitrary number of bytes containing the . character (decimal 46) on the stack. This buffer overflow could result in a crash (causing a denial of service). In a TLS client, this can be triggered by connecting to a malicious server. In a TLS server, this can be triggered if the server requests client authentication and a malicious client connects.

Recommendations Update to OpenSSL version 3.0.7 to resolve the issue. As a temporary workaround, consider restricting access to the vulnerable function ossl a2ulabel() until a patch is available. Avoid using the . character in email addresses in certificates to minimize the risk of exploitation.