SECURITY UPDATE: A NULL pointer dereference in rsa_cms_decrypt() when
processing CMS messages with RSA-OAEP encryption where pSourceFunc is
present but its parameters field is absent can trigger a crash, leading
to Denial of Service.
debian/patches/CVE-2026-28390.patch: use X509_ALGOR_get0 and
ASN1_STRING_* accessors to safely parse pSourceFunc; duplicate the
OAEP label before handing it to EVP_PKEY_CTX_set0_rsa_oaep_label.