CVE-2026-58392
MEDIUM 5.4OPNsense 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.
No known exploitation, public exploit, or elevated probability at this time. Track for changes.
Exploitation likelihood
0.3%chance of exploitation in 30 days · 20th percentile
Impact if exploited
5.4CVSS 3.1 · MEDIUM
- ConfidentialityLow
- IntegrityLow
- AvailabilityNone
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ⚠Privileges: Requires a low-privilege account
- ⚠User interaction: A user must take an action (click / open a file)
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept
No public PoC is currently catalogued.
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Tracked sources are checked daily for recent CVEs, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.
Data snapshot:
Weakness (CWE)
- CWE-79: : Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
References and research data (JSON)
All CVSS metrics
- MEDIUM 5.4 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N - MEDIUM 5.4 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
References
Exploit-tagged references (not proof of a PoC)
- https://github.com/opnsense/core/security/advisories/GHSA-h793-67jm-j4m5 CVE record · GitHub_M · Updated 2026-10-15T15:18:32.003Z
CVE record · CISA-ADP · Updated 2026-10-15T15:54:57.730Z
NVD · CVE-2026-58392 · Updated 2026-10-15T21:08:49.703
Advisories
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-102132 EUVD · EUVD-2026-102132
Technical & other
- https://github.com/opnsense/core/commit/a92d9514b5436c868f8f97138ebed507f6de423c CVE record · GitHub_M · Updated 2026-10-15T15:18:32.003Z
NVD · CVE-2026-58392 · Updated 2026-10-15T21:08:49.703 - https://github.com/opnsense/core/commit/ed04a154dc40967541be1388e9134e451be4199e CVE record · GitHub_M · Updated 2026-10-15T15:18:32.003Z
NVD · CVE-2026-58392 · Updated 2026-10-15T21:08:49.703 - https://hackerask.com/posts/opnsense CVE record · GitHub_M · Updated 2026-10-15T15:18:32.003Z
NVD · CVE-2026-58392 · Updated 2026-10-15T21:08:49.703