CVE-2026-119425

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.

CVSS v3 5.4 MEDIUM

5.4^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 2.5

Attack Vector ADJACENT_NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://abraxaslabs.tech/research/opnsense-captive-lastseen-roam
https://github.com/opnsense/core
https://github.com/opnsense/core/blob/26.7.7/src/opnsense/scripts/captiveportal/cp-background-process.py#L78
https://github.com/opnsense/core/commit/32dc2a3e52eefef5251077f315a0f3243eedb834
https://github.com/opnsense/core/commit/f46836d0c3d14e26d79214009bfbfa9a1eecab55
https://github.com/opnsense/core/security/advisories/GHSA-864r-q4j5-5mjq
https://www.vulncheck.com/advisories/opnsense-26.1.6-through-26.7.7-captive-portal-session-takeover-via-forged-arp

Configurations

No configuration.

History

30 Oct 2026, 12:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-30 12:16

Updated : 2026-10-30 19:23

NVD link : CVE-2026-119425

Mitre link : CVE-2026-119425

CVE.ORG link : CVE-2026-119425

JSON object : View

Products Affected

No product.

CWE

CWE-290

Authentication Bypass by Spoofing

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