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Vulnerabilities

Vulnerability · CVE-2026-58393

OPNsense is a FreeBSD based firewall and routing platform.

Published Oct 15, 2026 · catalog updated Oct 15, 2026 · OPNsense is a FreeBSD

Check if you run it

No confirmed exploitation is on record for CVE-2026-58393. EPSS is 0.43%. Act only if a listed version of OPNsense is a FreeBSD is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (OPNsense is a FreeBSD).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.9
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.43%
Remediation
Advisory link
Affected products
See sources for product scope

OPNsense is a FreeBSD based firewall and routing platform. Prior to version 26.1.11, the OpenVPN Client Specific Override common_name field accepts path traversal sequences and openvpn_csc_conf_write() concatenates the value into /var/etc/openvpn-csc/ / without normalization or a basename check. The affected event handlers are client_connect.php and user_pass_verify.php. An authenticated user with Client Specific Override privileges can store the traversal value, and a matching OpenVPN client-connect or authentication event causes a generated CSO file to be written outside the intended directory. The file content is generated OpenVPN configuration rather than arbitrary bytes, and practical exploitation requires the attacker to cause a matching common name or username to be processed. This issue is fixed in version 26.1.11.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-58393

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-58393. EPSS is 0.43%. Act only if a listed version of OPNsense is a FreeBSD is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-22: Path Traversal. EPSS 0.43%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 15, 2026 · NIST NVD

    Detected

    OPNsense is a FreeBSD based firewall and routing platform. Prior to version 26.1.11, the OpenVPN Client Specific Override common_name field accepts path traversal sequences and openvpn_csc_conf_write() concatenates the value into /var/etc/openvpn-csc/ / without normalization or a basename check. The affected event handlers are client_connect.php and user_pass_verify.php. An authenticated user with

  2. Oct 15, 2026 · NIST NVD

    Updated

    OPNsense is a FreeBSD based firewall and routing platform. Prior to version 26.1.11, the OpenVPN Client Specific Override common_name field accepts path traversal sequences and openvpn_csc_conf_write() concatenates the value into /var/etc/openvpn-csc/ / without normalization or a basename check. The affected event handlers are client_connect.php and user_pass_verify.php. An authenticated user with

Sources

  • CVE.orgVulnerability recordCVE-2026-58393

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-58393

    30-day exploitation probability 0.4%

    first.org
  • NIST NVDVulnerability recordCVE-2026-58393

    OPNsense is a FreeBSD based firewall and routing platform. Prior to version 26.1.11, the OpenVPN Client Specific Override common_name field accepts path traversal sequences and openvpn_csc_conf_write() concatenates the value into /var/etc/openvpn-csc/ / without

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.