CVE-2026-63442 (GCVE-0-2026-63442)
Vulnerability from cvelistv5 – Published: 2026-10-15 15:22 – Updated: 2026-10-16 17:13
VLAI
EPSS
VEX
Title
OPNsense: Log Forgery via Login Username CRLF in WebGUI Authentication → Pf Table IP Blocking
Summary
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.
Severity
8.1 (High)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-10-15 20:24 UTC
CWE
- CWE-117 - Improper Output Neutralization for Logs
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/opnsense/core/security/advisor… | x_refsource_CONFIRM |
| https://github.com/opnsense/core/commit/8bdaad95f… | x_refsource_MISC |
| https://github.com/opnsense/core/commit/c930ab586… | x_refsource_MISC |
Impacted products
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Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
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