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CVE-2026-34582

Botan has a TLS 1.3 certificate authentication bypass PUBLISHED

Description (CNA)

Botan is a C++ cryptography library. Prior to version 3.11.1, the TLS 1.3 implementation allowed ApplicationData records to be processed prior to the Finished message being received. A server which is attempting to enforce client authentication via certificates can by bypassed by a client which entirely omits Certificate, CertificateVerify, and the Finished message and instead sends application data records. This vulnerability is fixed in 3.11.1.

Affected (CNA)

Vendor / productVersions
randombit / botanaffected < 3.11.1

CWE

CWE-841

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.

redhat-SADP

A flaw was found in Botan, a C++ cryptography library. The TLS 1.3 implementation in Botan allows application data to be processed before the TLS handshake is fully completed. A remote attacker can exploit this by omitting critical client authentication messages, such as the Certificate, CertificateVerify, and Finished messages, and instead sending application data. This vulnerability enables a client to bypass server-enforced client authentication, potentially leading to unauthorized access.