CVE-2026-40854

{"id": "CVE-2026-40854", "cveTags": [], "metrics": {"cvssMetricV40": [{"type": "Secondary", "source": "cvd@cert.pl", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 8.7, "Automatable": "NOT_DEFINED", "attackVector": "ADJACENT", "baseSeverity": "HIGH", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "cvd@cert.pl", "affectedData": [{"vendor": "WNC", "product": "T-Mobile 5G Box IDU", "versions": [{"status": "affected", "version": "0", "lessThan": "1.1.0.651412", "versionType": "custom"}], "defaultStatus": "unaffected"}]}], "published": "2026-09-16T12:17:03.540", "references": [{"url": "https://cert.pl/posts/2026/09/CVE-2026-40854", "source": "cvd@cert.pl"}], "vulnStatus": "Received", "weaknesses": [{"type": "Primary", "source": "cvd@cert.pl", "description": [{"lang": "en", "value": "CWE-290"}]}], "descriptions": [{"lang": "en", "value": "WNC T-Mobile 5G Box IDU router contains an authentication bypass vulnerability in the portal.cgi component. The session verification mechanism improperly validates the sessionid cookie by checking for the existence of a corresponding file in /tmp/login_user. An attacker can bypass authentication by using directory entries such as \".\" or \"..\" in the cookie, allowing unauthorized access to the administration panel.This issue has been fixed in firmware version\u00a01.1.0.651412"}], "lastModified": "2026-09-16T12:17:03.540", "sourceIdentifier": "cvd@cert.pl"}