Out-of-bounds read in OpenSSL X509_VERIFY_PARAM_set1_email()
CVE-2026-42771 is a low-severity out-of-bounds read in OpenSSL's email address validation logic used by X509_VERIFY_PARAM_set1_email() and X509_VERIFY_PARAM_add1_email(). An internal helper function invoked by these APIs uses an incorrect length when validating the local part of an email address. As a result, the 64-octet limit for the local part may not be enforced correctly, and processing a crafted email address can cause an out-of-bounds read. The issue is reachable in application flows that validate email addresses through these APIs, including S/MIME message validation when a crafted From: address is supplied in an email message. OpenSSL states the affected code is outside the OpenSSL FIPS module boundary, so FIPS modules are not affected.
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