{"id":"CVE-2026-119425","aliases":["EUVD-2026-113805","GHSA-48x9-g485-9vgw","GHSA-864r-q4j5-5mjq"],"status":"published","title":"OPNsense 26.1.6 through 26.7.7 Captive Portal Session Takeover via Forged ARP","description":"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 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.","severity":{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00313,"percentile":0.24548,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-290"],"published":"2026-10-30T11:30:55Z","modified":"2026-11-01T02:47:28Z","products":[{"vendor":"opnsense","product":"core"}],"references":[{"url":"https://github.com/opnsense/core/security/advisories/GHSA-864r-q4j5-5mjq","tags":["vendor-advisory","advisory"]},{"url":"https://github.com/opnsense/core/commit/f46836d0c3d14e26d79214009bfbfa9a1eecab55","tags":["patch","fix"]},{"url":"https://github.com/opnsense/core/commit/32dc2a3e52eefef5251077f315a0f3243eedb834","tags":["patch","fix"]},{"url":"https://github.com/opnsense/core/blob/26.7.7/src/opnsense/scripts/captiveportal/cp-background-process.py#L78","tags":["technical-description","article"]},{"url":"https://abraxaslabs.tech/research/opnsense-captive-lastseen-roam","tags":["third-party-advisory","advisory"]},{"url":"https://github.com/opnsense/core","tags":["product","package"]},{"url":"https://www.vulncheck.com/advisories/opnsense-26.1.6-through-26.7.7-captive-portal-session-takeover-via-forged-arp","tags":["third-party-advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-119425","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-48x9-g485-9vgw"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/119xxx/CVE-2026-119425.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-119425","title":"OPNsense 26.1.6 through 26.7.7 Captive Portal Session Takeover via Forged ARP","description":"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 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.","status":"published","published":"2026-10-30T11:30:55.121Z","modified":"2026-10-30T15:55:05.938Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium","assessor":"cna"},{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-290"],"updated_at":"2026-11-02T14:20:10.143031Z"}],"euvd":[{"id":"EUVD-2026-113805","description":"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 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.","status":"published","published":"2026-10-30T11:30:55Z","modified":"2026-10-30T15:55:05Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"updated_at":"2026-11-02T16:59:05.913237Z"}],"ghsa":[{"id":"GHSA-48x9-g485-9vgw","title":"OPNsense core 26.1.6 through 26.7.7 contains an authentication bypass vulnerability in the...","description":"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 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.","status":"published","published":"2026-10-30T12:31:19Z","modified":"2026-10-30T12:31:25Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/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","level":"medium"},{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-290"],"updated_at":"2026-11-02T15:14:42.307242Z"}],"nvd":[{"id":"CVE-2026-119425","description":"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 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.","status":"published","published":"2026-10-30T12:16:39.527Z","modified":"2026-10-30T19:23:25.493Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/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","level":"medium","assessor":"secondary"},{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-290"],"updated_at":"2026-11-02T14:13:04.940026Z"}],"osv":[{"id":"CVE-2026-119425","title":"OPNsense 26.1.6 through 26.7.7 Captive Portal Session Takeover via Forged ARP","description":"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 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.","status":"published","published":"2026-10-30T11:30:55.121Z","modified":"2026-11-01T02:47:28.800200221Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-290"],"updated_at":"2026-11-02T15:44:57.008854Z"}]}}