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TI-2026-74823 Aliases CVE-2026-58393

Path traversal in OPNsense OpenVPN override common_name writes files

Priority MEDIUM 60CWE-22Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
High
Impact type
—
Confidentiality · integrity · availability
None · High · Low
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

OPNsense core before 26.1.11 is affected. The OpenVPN Client Specific Override common_name field accepts path traversal sequences that are concatenated into a generated file path without normalization or a basename check (CWE-22). An authenticated user with Client Specific Override privileges can store such a value, and a matching OpenVPN client connect or authentication event writes a generated configuration file outside the intended directory. Exploitation requires a matching common name or username to be processed.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

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/<vpnid>/<common_name> 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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00433 37th percentileScored 2026-11-07
Fix Fixed core (opnsense): 26.1.11

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
opnsensecorebefore 26.1.1126.1.11Patch availableCNA
  • core Vendoropnsense Affected before 26.1.11 Fixed in 26.1.11 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:opnsense:opnsense:*:*:*:*:*:*:*:*——opnsense
  • cpe:2.3:a:opnsense:opnsense:*:*:*:*:*:*:*:* Versions — — ·opnsense

Remediation

Upgrade OPNsense core to version 26.1.11, which fixes this issue. Versions before 26.1.11 are affected.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA core (opnsense) Fixed in 26.1.11

Timeline

  1. 2026-10-16 Threatist record created from CVE-2026-58393

References

Other 3

  • TI-2023-20247 A command injection vulnerability in the component /api/cron/settings/setJob/ of OPNsense… CVSS 3.1CRITICAL 9.8
  • TI-2023-20243 Insecure permissions in the configuration directory (/conf/) of OPNsense Community… CVSS 3.1CRITICAL 9.8
  • TI-2023-20240 A command injection vulnerability in the component diag_backup.php of OPNsense Community… CVSS 3.1CRITICAL 9.8
  • TI-2023-11947 DECISO OPNsense 23.1 does not impose rate limits for authentication, allowing attackers… CVSS 3.1CRITICAL 9.8
  • TI-2026-74819 Path traversal in OPNsense GeoIP importer allows root code execution CVSS 3.1CRITICAL 9.9
  • TI-2023-20246 /ui/cron/item/open in the Cron component of OPNsense Community Edition before 23.7 and… CVSS 3.1CRITICAL 9.6
See all 54 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences