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TI-2026-74826 Aliases CVE-2026-63442

OPNsense: Log Forgery via Login Username CRLF in WebGUI Authentication → Pf Table IP Blocking

Priority LOW 35CWE-117Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00285 21st percentileScored 2026-11-07
Fix Fixed core (opnsense): 26.1.11

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
opnsensecorebefore 26.1.1126.1.11Patch availableCNA
  • core Vendoropnsense Affected before 26.1.11 Fixed in 26.1.11 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:opnsense:opnsense:*:*:*:*:*:*:*:*——opnsense
  • cpe:2.3:a:opnsense:opnsense:*:*:*:*:*:*:*:* Versions — — ·opnsense

Remediation

  • Fix · CNA core (opnsense) Fixed in 26.1.11

Timeline

  1. 2026-10-16 Threatist record created from CVE-2026-63442
  2. 2026-10-16 Priority changed: MEDIUM → LOW
  3. 2026-10-16 CISA SSVC decision points changed

References

Other 3

  • TI-2023-20247 A command injection vulnerability in the component /api/cron/settings/setJob/ of OPNsense… CVSS 3.1CRITICAL 9.8
  • TI-2023-20243 Insecure permissions in the configuration directory (/conf/) of OPNsense Community… CVSS 3.1CRITICAL 9.8
  • TI-2023-20240 A command injection vulnerability in the component diag_backup.php of OPNsense Community… CVSS 3.1CRITICAL 9.8
  • TI-2023-11947 DECISO OPNsense 23.1 does not impose rate limits for authentication, allowing attackers… CVSS 3.1CRITICAL 9.8
  • TI-2026-74819 Path traversal in OPNsense GeoIP importer allows root code execution CVSS 3.1CRITICAL 9.9
  • TI-2023-20246 /ui/cron/item/open in the Cron component of OPNsense Community Edition before 23.7 and… CVSS 3.1CRITICAL 9.6
See all 54 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences