Vulnerability in Opnsense Core
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/opnsense/core/security/advisories/GHSA-864r-q4j5-5mjq (vendor-advisory)
- github.com/opnsense/core/commit/f46836d0c3d14e26d79214009bfbfa9a1eecab55 (patch)
- github.com/opnsense/core/commit/32dc2a3e52eefef5251077f315a0f3243eedb834 (patch)
- github.com/opnsense/core/blob/26.7.7/src/opnsense/scripts/captiveportal/cp-back… (technical-description)
- abraxaslabs.tech/research/opnsense-captive-lastseen-roam (third-party-advisory)
- github.com/opnsense/core (product)
- www.vulncheck.com/advisories/opnsense-26.1.6-through-26.7.7-captive-portal-sess… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-119425?
- CVE-2026-119425 is a medium-severity vulnerability in Opnsense Core, classified under Authentication Bypass by Spoofing. CVSS score: 5.4/10. Published 2026-10-30.
- How severe is CVE-2026-119425?
- Medium severity. CVSS v3 base score is 5.4 out of 10.