OPNsense 26.1.6 through 26.7.7 Captive Portal Session Takeover via Forged ARP
Summary
| CVE | CVE-2026-119425 |
|---|---|
| State | PUBLISHED |
| Assigner | VulnCheck |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-30 12:16:39 UTC |
| Updated | 2026-10-30 19:23:25 UTC |
| 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. |
Risk And Classification
Primary CVSS: v4.0 5.3 MEDIUM from [email protected]
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
Problem Types: CWE-290 | CWE-290 Authentication Bypass by Spoofing
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 5.3 | MEDIUM | 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/C... |
| 4.0 | CNA | CVSS | 5.3 | MEDIUM | 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 |
| 3.1 | [email protected] | Secondary | 5.4 | MEDIUM | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |
| 3.1 | CNA | CVSS | 5.4 | MEDIUM | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |
CVSS v4.0 Breakdown
Attack Vector
AdjacentAttack Complexity
LowAttack Requirements
NonePrivileges Required
NoneUser Interaction
NoneConfidentiality
LowIntegrity
LowAvailability
NoneSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS: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
CVSS v3.1 Breakdown
Attack Vector
AdjacentAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
LowIntegrity
LowAvailability
NoneCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/opnsense/core/commit/f46836d0c3d14e26d79214009bfbfa9a1eecab55 | [email protected] | github.com | |
| abraxaslabs.tech/research/opnsense-captive-lastseen-roam | [email protected] | abraxaslabs.tech | |
| github.com/opnsense/core/commit/32dc2a3e52eefef5251077f315a0f3243eedb834 | [email protected] | github.com | |
| github.com/opnsense/core/blob/26.7.7/src/opnsense/scripts/captiveportal/... | [email protected] | github.com | |
| github.com/opnsense/core | [email protected] | github.com | |
| github.com/opnsense/core/security/advisories/GHSA-864r-q4j5-5mjq | [email protected] | github.com | |
| www.vulncheck.com/advisories/opnsense-26.1.6-through-26.7.7-captive-portal-sess... | [email protected] | www.vulncheck.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: lujiefsi (en)
CNA: Abraxas Labs (en)
There are currently no legacy QID mappings associated with this CVE.