Issue summary: The AES-SIV cipher implementation contains a bug that causesit to ignore empty associated data entries which are unauthenticated asa consequence.Impact summary: Applications that use the AES-SIV algorithm and want toauthenticate empty data entries as associated data can be mislead by removingadding or reordering such empty entries as these are ignored by the OpenSSLimplementation. We are currently unaware of any such applications.The AES-SIV algorithm allows for authentication of multiple associateddata entries along with the encryption. To authenticate empty data theapplication has to call EVP_EncryptUpdate withNULL pointer as the output buffer and 0 as the input buffer length.The AES-SIV implementation in OpenSSL just returns success for such a callinstead of performing the associated data authentication operation.The empty data thus will not be authenticated.As this issue does not affect non-empty associated data authentication andwe expect it to be rare for an application to use empty associated dataentries this is qualified as Low severity issue. Issue summary: Checking excessively long DH keys or parameters may be very slow.Impact summary: Applications that use the functions DH_check, DH_check_exor EVP_PKEY_param_check to check a DH key or DH parameters may experience longdelays. Where the key or parameters that are being checked have been obtainedfrom an untrusted source this may lead to a Denial of Service.The function DH_check performs various checks on DH parameters. One of thosechecks confirms that the modulus is not too large. Trying to usea very large modulus is slow and OpenSSL will not normally use a modulus whichis over 10,000 bits in length.However the DH_check function checks numerous aspects of the key or parametersthat have been supplied. Some of those checks use the supplied modulus valueeven if it has already been found to be too large.An application that calls DH_check and supplies a key or parameters obtainedfrom an untrusted source could be vulernable to a Denial of Service attack.The function DH_check is itself called by a number of other OpenSSL functions.An application calling any of those other functions may similarly be affected.The other functions affected by this are DH_check_ex andEVP_PKEY_param_check.Also vulnerable are the OpenSSL dhparam and pkeyparam command line applicationswhen using the '-check' option.The OpenSSL SSL/TLS implementation is not affected by this issue.The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this issue. Issue summary: Checking excessively long DH keys or parameters may be very slow.Impact summary: Applications that use the functions DH_check, DH_check_exor EVP_PKEY_param_check to check a DH key or DH parameters may experience longdelays. Where the key or parameters that are being checked have been obtainedfrom an untrusted source this may lead to a Denial of Service.The function DH_check performs various checks on DH parameters. After fixingCVE-2023-3446 it was discovered that a large q parameter value can also triggeran overly long computation during some of these checks. A correct q value,if present, cannot be larger than the modulus p parameter, thus it isunnecessary to perform these checks if q is larger than p.An application that calls DH_check and supplies a key or parameters obtainedfrom an untrusted source could be vulnerable to a Denial of Service attack.The function DH_check is itself called by a number of other OpenSSL functions.An application calling any of those other functions may similarly be affected.The other functions affected by this are DH_check_ex andEVP_PKEY_param_check.Also vulnerable are the OpenSSL dhparam and pkeyparam command line applicationswhen using the "-check" option.The OpenSSL SSL/TLS implementation is not affected by this issue.The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this issue