{"id":"CVE-2026-119425","title":"OPNsense 26.1.6 through 26.7.7 Captive Portal Session Takeover via Forged ARP","summary":"OPNsense core 26.1.6 through 26.7.7 contains an authentication bypass vulnerability in the captive portal roaming feature that lets unauthenticated attackers hijack authorized client sessions by spoofing unauthenticated MAC-to-IP observa…","severity":"medium","cvss":5.4,"cvssVector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","cvssSource":"cna","cwe":["CWE-290"],"vendor":"opnsense","product":"core","affected":["core >= 26.1.6 <= 26.7.7"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-30T15:20:58.656589Z"},"published":"2026-10-30","updated":"2026-10-30","sourceUpdated":"2026-10-30T15:55:05.938Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-119425","references":[{"url":"https://github.com/opnsense/core/security/advisories/GHSA-864r-q4j5-5mjq","label":"GitHub Security Advisory (GHSA-864r-q4j5-5mjq)"},{"url":"https://github.com/opnsense/core/commit/f46836d0c3d14e26d79214009bfbfa9a1eecab55","label":"Incomplete fix"},{"url":"https://github.com/opnsense/core/commit/32dc2a3e52eefef5251077f315a0f3243eedb834","label":"Incomplete fix (stable/26.7)"},{"url":"https://github.com/opnsense/core/blob/26.7.7/src/opnsense/scripts/captiveportal/cp-background-process.py#L78"},{"url":"https://abraxaslabs.tech/research/opnsense-captive-lastseen-roam"},{"url":"https://github.com/opnsense/core"},{"url":"https://www.vulncheck.com/advisories/opnsense-26.1.6-through-26.7.7-captive-portal-session-takeover-via-forged-arp","label":"VulnCheck Advisory: OPNsense 26.1.6 through 26.7.7 Captive Portal Session Takeover via Forged ARP"}],"tags":["cve.org"],"epss":0.00313,"epssPercentile":0.24369,"ingestedAt":"2026-11-05T16:07:30.523Z","slug":"CVE-2026-119425","body":"## Overview\n\nOPNsense core 26.1.6 through 26.7.7 contains an authentication bypass vulnerability in the captive portal roaming feature that lets unauthenticated attackers hijack authorized client sessions by spoofing unauthenticated MAC-to-IP observations. Attackers on the same Layer-2 segment can send forged gratuitous ARP replies binding their IP to a victim's MAC, gaining portal access with traffic attributed to the victim.\n\n## Affected\n\n- `core >= 26.1.6 <= 26.7.7`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":29.7,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}