Issue summary: Calling the OpenSSL API function SSL_select_next_proto with an
empty supported client protocols buffer may cause a crash or memory contents to
be sent to the peer.
Impact summary: A buffer overread can have a range of potential consequences
such as unexpected application beahviour or a crash. In particular this issue
could result in up to 255 bytes of arbitrary private data from memory being sent
to the peer leading to a loss of confidentiality. However, only applications
that directly call the SSL_select_next_proto function with a 0 length list of
supported client protocols are affected by this issue. This would normally neve
Excessive time spent checking DSA keys and parameters
Issue summary: Checking excessively long DSA keys or parameters may be very
slow.
Impact summary: Applications that use the functions EVP_PKEY_param_check()
or EVP_PKEY_public_check() to check a DSA public key or DSA parameters may
experience long delays. Where the key or parameters that are being checked
have been obtained from an untrusted source this may lead to a Denial of
Service.
The functions EVP_PKEY_param_check() or EVP_PKEY_public_check() perform
various checks on DSA parameters. Some of those computations take a long time
if the modulus (`p` parameter) is too large.
Trying to use a very large modulus is slow and OpenSSL will not
Unbounded memory growth with session handling in TLSv1.3
Issue summary: Some non-default TLS server configurations can cause unbounded
memory growth when processing TLSv1.3 sessions
Impact summary: An attacker may exploit certain server configurations to trigger
unbounded memory growth that would lead to a Denial of Service
This problem can occur in TLSv1.3 if the non-default SSL_OP_NO_TICKET option is
being used (but not if early_data support is also configured and the default
anti-replay protection is in use). In this case, under certain conditions, the
session cache can get into an incorrect state and it will fail to flush properly
as it fills. The session cache will continue to grow in an unb