Vulnerability in Botan Project
CVE-2026-34582
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.
EPSS: 0.002 (14.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
Affected products
- Botan_project Botan
- Randombit Botan — versions < 3.11.1
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-34582?
- CVE-2026-34582 is a critical-severity vulnerability in Botan Project, classified under Improper Enforcement of Behavioral Workflow. CVSS score: 9.1/10. Published 2026-04-07.
- How severe is CVE-2026-34582?
- Critical severity. CVSS v3 base score is 9.1 out of 10.