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CVE-2026-63442— OPNsense: Log Forgery via Login Username CRLF in WebGUI Authentication → Pf Table IP Blocking

Quick assessment

Affected
opnsense core
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

OPNsense 是一个基于 FreeBSD 的防火墙和路由平台。在 26.1.11 版本之前，未认证的 WebGUI 登录界面的 字段接受回车符（CR）和换行符（LF）。这些字符在处理过程中未经过 充分清理，通过 配置被传递到 程序目标，并最终进入由 处理的日志流。 消费者在处理输入时使用了 函数，该函数会将注入的非法片段解析为独立的认证事件。此外，它会从伪造的日志行中提取第一个语法上有效的 IP 地址。因此，具有网络访问权限的攻击者若能接触到登录页面，就可以伪造其他 IP 地址的失败登录事件，导致该 IP 被加

CVSS 8.1 · High EPSS 0.29% · P20

Affected Version Matrix 1

VendorProduct Version RangeStatus
opnsense core < 26.1.11 affected
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I. Basic Information for CVE-2026-63442

Vulnerability Information
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Vulnerability Title
OPNsense: Log Forgery via Login Username CRLF in WebGUI Authentication → Pf Table IP Blocking
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
日志输出的转义处理不恰当
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
opnsense core < 26.1.11 -

II. Public POCs for CVE-2026-63442

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III. Intelligence Information for CVE-2026-63442

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Patches & Fixes for CVE-2026-63442 (2)

Vendor Advisories for CVE-2026-63442 (1)

Same Patch Batch · opnsense · 2026-10-15 · 10 CVEs total

CVE-2026-57155 9.9 CRITICAL OPNsense: Root RCE via Arbitrary File Write in GeoIP Alias Importer
CVE-2026-58390 8.0 HIGH OPNsense: Stored XSS to root RCE via OpenVPN client common_name in status views
CVE-2026-53582 7.1 HIGH OPNsense: XPATH Injection can disclose any secret in config.xml
CVE-2026-71490 7.1 HIGH OPNsense: Direct comma-separated user privileges bypass OPNsense MVC read-only write prote
CVE-2026-58393 5.9 MEDIUM OPNsense: OpenVPN Client Specific Override common_name allows path traversal in generated
CVE-2026-58391 5.4 MEDIUM OPNsense: Stored XSS in Firewall Rules/NAT pages via a HTML-attribute breakout
CVE-2026-58392 5.4 MEDIUM OPNsense: Stored XSS in Services: NTP GPS
CVE-2026-58394 5.2 MEDIUM OPNsense: Stored XSS in Administration Settings via Certificate Description
CVE-2026-58395 4.3 MEDIUM OPNsense: XPath injection in MVC safe-delete

IV. Related Vulnerabilities

Same product: core
Same vendor: opnsense
Same weakness: CWE-117

V. Comments for CVE-2026-63442

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