Vulnerability in Opnsense Core
CVE-2026-119423
OPNsense core before 26.7.8 contains a log injection vulnerability that allows unauthenticated attackers to plant victim IP addresses in the lockout_handler by submitting crafted WebGUI login usernames. Attackers can submit usernames like 'Invalid user <victim-ip>' repeatedly to add the victim to the sshlockout table, blocking SSH and WebGUI access and killing its pf states.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
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/commit/14f8f7dd1d5f06522d60794a7beeac7adb9eca68 (patch)
- github.com/opnsense/core/commit/2076f2c195bf9537ec220f0e5d6aff998f057410 (patch)
- github.com/opnsense/core/blob/26.7.7/src/opnsense/mvc/app/library/OPNsense/Auth… (technical-description)
- github.com/opnsense/core/blob/26.7.7/src/opnsense/scripts/syslog/lockout_handler (technical-description)
- github.com/opnsense/core/security/advisories/GHSA-2v2x-m4j7-76pv (vendor-advisory)
- abraxaslabs.tech/research/opnsense-lockout-factory-ip (third-party-advisory)
- github.com/opnsense/core (product)
- www.vulncheck.com/advisories/opnsense-core-before-26.7.8-lockout-ip-planting-vi… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-119423?
- CVE-2026-119423 is a medium-severity vulnerability in Opnsense Core, classified under Improper Output Neutralization for Logs. CVSS score: 5.3/10. Published 2026-10-30.
- How severe is CVE-2026-119423?
- Medium severity. CVSS v3 base score is 5.3 out of 10.