CVE-2026-58392 OPNsense: Stored XSS in Services: NTP GPS
An attacker with NTP GPS privileges can inject scripts that execute in other users' sessions, potentially leading to account takeover or administrative actions.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-58392?
CVE-2026-58392 is a medium-severity cross-site scripting vulnerability in opnsense core, published on 15 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-79
Which versions are affected by CVE-2026-58392?
How do I fix CVE-2026-58392?
No fix has been published for CVE-2026-58392 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-58392 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58392 exists.
Sources
Also known as GHSA-h793-67jm-j4m5.