CVE Catalog

CVE-2026-119425

MediumCVSS 5.4
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.31%

24th percentile - higher than 24% of all known CVEs

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 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 Assessment

An attacker can gain network access with the victim's privileges, and traffic may be misattributed to the victim, complicating auditing and accounting. It requires presence on the same L2 segment.

Recommendation

Update OPNsense to version 26.7.8 or later and consider deploying ARP spoofing protections (e.g., DHCP snooping, dynamic ARP inspection) in the network.

Other vulnerabilities in OPNsense

See all
Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS