PT-2026-52599 · Wolfssl · Wolfssl
Published
2026-06-25
·
Updated
2026-06-25
·
CVE-2026-55962
CVSS v4.0
6.0
Medium
| Vector | AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
TLS 1.3 post-handshake authentication (PHA) issue where a server could accept a client's Finished message without the client having sent a Certificate and CertificateVerify. The post-handshake-auth exemption that allows an empty/absent peer certificate was only intended for the initial handshake, but it was also being applied while a post-handshake CertificateRequest was still outstanding. The check is now scoped to the initial handshake only: on the server, once a post-handshake CertificateRequest has been sent (certReqCtx is set), a peer certificate and a valid CertificateVerify are required again before the Finished is accepted, with empty-certificate handling following the configured verify mode (FAIL IF NO PEER CERT) just as during first-handshake client authentication. Only affects TLS 1.3 servers built with post-handshake authentication support (WOLFSSL POST HANDSHAKE AUTH / --enable-postauth, included in --enable-all) that enable WOLFSSL VERIFY POST HANDSHAKE and request a client certificate after the handshake via wolfSSL request certificate(). Clients, and servers that do not use post-handshake authentication, are unaffected.
Fix
Improper Authentication
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Weakness Enumeration
Related Identifiers
Affected Products
Wolfssl