CVE-2026-34582
Botan Project Botan 3.0.0 – 3.11.0
Raw 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/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:XSummary
CVE-2026-34582 is a high-severity Improper Enforcement of Behavioral Workflow (CWE-841) vulnerability in Botan Project Botan. Its CVSS base score is 8.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique External Remote Services (T1133); ranked at the 14th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and IA-11 (Re-authentication) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-34582 affects Botan, a C++ cryptography library, specifically its TLS 1.3 implementation in versions prior to 3.11.1. The vulnerability (CWE-841) enables the processing of ApplicationData records before the Finished message is received during the TLS handshake. This flaw allows a server enforcing client authentication via certificates to be bypassed, as rated with a CVSS v3.1 base score of 9.1 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N).
A remote attacker acting as a TLS client can exploit this by omitting the Certificate, CertificateVerify, and Finished messages entirely, instead sending ApplicationData records directly. No privileges or user interaction are required, enabling low-complexity network-based attacks against vulnerable Botan-based servers. Successful exploitation bypasses mandatory client certificate authentication, potentially granting unauthorized access to protected resources and compromising confidentiality and integrity.
The Botan security advisory at https://github.com/randombit/botan/security/advisories/GHSA-pxcj-9ppx-g86g details the issue and confirms the fix in version 3.11.1, recommending immediate upgrades for all users of affected versions implementing TLS 1.3 servers with client certificate requirements.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-19948
Vulnerability Data
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…
more
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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V7.2.1
Mitigating Controls (NIST 800-53 r5) AI
Access enforcement can require each successive workflow step to present the proper authorization context before proceeding.
Re-authentication requirements can be placed at critical workflow steps to ensure the actor has performed prior behaviors.
SI-10 directly requires validation of information inputs, structurally preventing failures to handle missing special elements.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure development practices directly address proper workflow enforcement during design and coding.
Identifying and recording vulnerabilities enables remediation of missing-special-element flaws before exploitation.
Enforcing authorization policies can include sequence constraints on multi-step actions.
Hardened configuration baselines can embed required workflow ordering rules.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect workflow bypasses but does not enforce them at runtime.
Secure development lifecycle requires explicit workflow enforcement in multi-step processes.
Application security requirements include sequencing and state-transition rules for critical workflows.
Secure architecture principles address proper ordering of security-critical operations.
Secure coding practices can prevent missing workflow checks but do not define the control itself.
Change management can require workflow adherence for changes but is not the primary mitigation.