CVE-2026-34582CWE-841

Botan has a TLS 1.3 certificate authentication bypass

High · published April 7, 2026

CVSS v4.0
8.7
EPSS
0%
Percentile
30.7
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
8.7 · HIGH
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
EPSS
0.00379 · 30.7th percentile
Weakness
CWE-841 · Improper Enforcement of Behavioral Workflow
Published
2026-04-07T21:13Z
EPSS history
Timeline
  • 07 APR 21:13Z
    Botan has a TLS 1.3 certificate authentication bypass
    cvelistv5