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Vulnerabilities

Vulnerability · CVE-2026-63442

OPNsense is a FreeBSD based firewall and routing platform.

Published Oct 15, 2026 · catalog updated Oct 15, 2026 · OPNsense is a FreeBSD

Check if you run it

No confirmed exploitation is on record for CVE-2026-63442. EPSS is 0.29%. Act only if a listed version of OPNsense is a FreeBSD is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (OPNsense is a FreeBSD).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.29%
Remediation
Advisory link
Affected products
See sources for product scope

OPNsense is a FreeBSD based firewall and routing platform. Prior to version 26.1.11, the unauthenticated WebGUI login usernamefld accepts carriage-return and line-feed characters that survive LOG_AUTH processing through syslog-ng-lockout.conf into the syslog-ng program destination feeding lockout_handler. The consumer's readline() processing treats an injected fragment as a separate authentication event and selects the first syntactically valid IP address from the forged line. An attacker with network access to the login page can forge failure events for another IP, causing that IP to be added to the sshlockout PF table and its active states to be killed, or forge accepted events that reset an attacker's own brute-force counter. This can block administrative, DNS, gateway, or monitoring addresses and can bypass password-guessing lockout without authentication. This issue is fixed in version 26.1.11.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-63442

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-63442. EPSS is 0.29%. Act only if a listed version of OPNsense is a FreeBSD is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-117. EPSS 0.29%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 15, 2026 · NIST NVD

    Detected

    OPNsense is a FreeBSD based firewall and routing platform. Prior to version 26.1.11, the unauthenticated WebGUI login usernamefld accepts carriage-return and line-feed characters that survive LOG_AUTH processing through syslog-ng-lockout.conf into the syslog-ng program destination feeding lockout_handler. The consumer's readline() processing treats an injected fragment as a separate authentication

Sources

  • CVE.orgVulnerability recordCVE-2026-63442

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-63442

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2026-63442

    OPNsense is a FreeBSD based firewall and routing platform. Prior to version 26.1.11, the unauthenticated WebGUI login usernamefld accepts carriage-return and line-feed characters that survive LOG_AUTH processing through syslog-ng-lockout.conf into the syslog-ng program destinatio

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.