CVE-2026-63442
OPNsense: Log Forgery via Login Username CRLF in WebGUI Authentication → Pf Table IP Blocking
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High8.1 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H |
| NVDNVD · Deferred | 3.1 | High8.1 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.29% · top 79% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.1.
Weakness
Affected products
References (3)
- https://github.com/opnsense/core/security/advisories/GHSA-2v2x-m4j7-76pv (opens in a new tab)x_refsource_CONFIRM
- https://github.com/opnsense/core/commit/8bdaad95f405f4587bb83bf35aa652ca493cc2a4 (opens in a new tab)x_refsource_MISC
- https://github.com/opnsense/core/commit/c930ab586ffe2d2e010e5135657e5e054316ff58 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-63442)Record last updated .