CVE-2026-2673

A key group selection preference flaw has been discovered in OpenSSL. An OpenSSL TLS 1.3 server may fail to negotiate the expected preferred key exchange group when its key exchange group configuration includes the default by using the "DEFAULT" keyword. A less preferred key exchange may be used even when a more preferred group is supported by both client and server, if the group was not included among the client's initial predicated keyshares. This will sometimes be the case with the new hybrid post-quantum groups, if the client chooses to defer their use until specifically requested by the server. No OpenSSL FIPS modules are affected by this issue, the code in question lies outside the FIPS boundary.