OPNsense up to 26.1.10 Ntp Gps Page services_ntpd_gps.php base64_decode initcmd cross-site request forgery

Summaryinfo

A vulnerability, which was classified as problematic, was found in OPNsense up to 26.1.10. This issue affects the function base64_decode of the file src/www/services_ntpd_gps.php of the component Ntp Gps Page. Executing a manipulation of the argument initcmd can lead to cross-site request forgery. This vulnerability appears as CVE-2026-58392. The attack may be performed from remote. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in OPNsense up to 26.1.10. This vulnerability affects the function base64_decode of the file src/www/services_ntpd_gps.php of the component Ntp Gps Page. The manipulation of the argument initcmd with an unknown input leads to a cross-site request forgery vulnerability. The CWE definition for the vulnerability is CWE-352. The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request. As an impact it is known to affect integrity. CVE summarizes:

OPNsense is a FreeBSD based firewall and routing platform. Prior to version 26.1.11, the NTP GPS page stores the operator-supplied initcmd value in base64 form, applies legacy_html_escape_form_data() to the encoded string, and then uses base64_decode() to decode the value directly into the GPS initialization-command textarea in src/www/services_ntpd_gps.php. Because decoding occurs after escaping, stored HTML remains unescaped at the output sink. A user with page-services-ntp-gps privilege can store a value that closes the textarea, and script executes in the session of any user who later opens the GPS page. The script can read CSRF material and perform authenticated actions, including actions available to an administrator. This issue is fixed in version 26.1.11.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-58392 since 06/30/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available.

By approaching the search of inurl:src/www/services_ntpd_gps.php it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 26.1.11 eliminates this vulnerability.

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Productinfo

Name

• OPNsense

Version

• 26.1.0
• 26.1.1
• 26.1.2
• 26.1.3
• 26.1.4
• 26.1.5
• 26.1.6
• 26.1.7
• 26.1.8
• 26.1.9
• 26.1.10

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