Issue summary: In a server or client configuration with RFC7250 Raw Public Keys (RPKs) enabled, and only the private key (with no associated certificate) configured locally, a NULL pointer dereference may occur when the remote peer solicits raw public keys and also sends the typically omitted "signature_algorithms_cert" TLS extension.
Impact summary: The impact is limited to a possible Denial of Service as a result of an application abort, no data disclosure or remote command execution are possible.
CWE: CWE-476: NULL Pointer Dereference
Description: While a passing comment in sample code in the documentation suggests that key-only RPK configurations are supported, the best-practice RPK configuration is to always configure a corresponding certificate (possibly self-signed or signed by any convenient CA).
When the private key is configured along with a matching certificate, the "signature_algorithms_cert" extension is handled reliably even without the fix, and peer clients or servers that don't support raw public keys may be able to complete a TLS connection by pinning or verifying the corresponding certificate or its public key.
Deployments that prefer to configure just a private key with no certificate need to upgrade to an updated release as noted below.
FIPS impact: no
No FIPS modules are affected by this issue, as the SSL protocol implementation is outside the OpenSSL FIPS module boundary.
3.4.73.5.83.6.44.0.2Exploitability
AV:NAC:LPR:NUI:NScope
S:UImpact
C:NI:NA:H7.5/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HMemory Safety