CVE-2026-14457: RPK Server Signature Algorithm Selection Can Dereference a Missing Certificate
A flaw was found in OpenSSL. 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 "signaturealgorithmscert" TLS extension.
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.
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 "signaturealgorithmscert" 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.
No FIPS modules are affected by this issue, as the SSL protocol implementation is outside the OpenSSL FIPS module boundary.
OpenSSL 4.0, 3.6, 3.5, and 3.4 are vulnerable to this issue. OpenSSL 3.0, 1.1.1, and 1.0.2 are not affected by this issue. OpenSSL 4.0 users should upgrade to OpenSSL 4.0.2. OpenSSL 3.6 users should upgrade to OpenSSL 3.6.4. OpenSSL 3.5 users should upgrade to OpenSSL 3.5.8. OpenSSL 3.4 users should upgrade to OpenSSL 3.4.7.
Other sources
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 "signaturealgorithmscert" TLS extension.
— Launchpad
RPK Server Signature Algorithm Selection Can Dereference a Missing Certificate
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/opensslto a version that resolves this vulnerability.Fixed in 3.0.20-1~deb12u2Fixed in 3.0.22-1~deb12u2Fixed in 3.5.7-1~deb13u2Fixed in 3.5.7-1~deb13u3Fixed in 3.6.5-1 - Upgrade
Upgrade
OpenSSLto a version that resolves this vulnerability.Fixed in 3.4.7 - Upgrade
Upgrade
OpenSSLto a version that resolves this vulnerability.Fixed in 3.5.8 - Upgrade
Upgrade
OpenSSLto a version that resolves this vulnerability.Fixed in 3.6.4 - Upgrade
Upgrade
OpenSSLto a version that resolves this vulnerability.Fixed in 4.0.2 - Configuration
Configure a corresponding certificate with the private key for RPK deployments, possibly self-signed or signed by any convenient CA; avoid key-only RPK configurations.
OpenSSL RFC7250 Raw Public Keys (RPK) configuration Corresponding certificate for configured private key = configured
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Server or client deployments with RFC7250 Raw Public Keys enabled are exposed when they configure only a local private key and no associated certificate. Configurations that pair the private key with a matching certificate handle the relevant TLS extension reliably even without the fix.
What must a remote peer do to trigger the denial of service?
The peer must solicit raw public keys and send the normally omitted "signature_algorithms_cert" TLS extension. Under the affected key-only RPK configuration, this can cause the application to abort.
What can be done if the fix cannot be deployed immediately?
Configure a matching certificate for the locally configured private key. The certificate may be self-signed or signed by a convenient CA; this also may allow peers without RPK support to connect by pinning or verifying the certificate or its public key.
How can an operator determine whether a deployment is at risk?
Review TLS configuration for RFC7250 RPK use and check whether the local identity consists only of a private key without a corresponding certificate. Such a deployment is at risk if it accepts connections from peers that can request RPKs and supply the "signature_algorithms_cert" extension.