OPNsense: OpenVPN Client Specific Override common_name allows path traversal in generated CSO files
CVSS score
5.9
EPSS probability
—
Risk score
0.6
Published
4 h ago
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Impact on My Inventory
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Vulnerability description
CVE AI research
DayBreach AI Explanation
Verified against sourcesSources read
2
Source agreement
Tam uyum
Evidence confidence
%63
Short explanation
CVE-2026-58393 in OPNsense core allows an authenticated user with Client Specific Override privileges to inject path traversal sequences. The vulnerability occurs because openvpn_csc_conf_write() concatenates values without normalization or a basename check. This can cause generated Client Specific Override files to be written outside the intended directory during matching OpenVPN events.
It matters because it allows attackers with specific privileges to compromise file placement and write OpenVPN configurations outside intended directories.
What should be done?
- Update OPNsense to version 26.1.11 or later
- Follow vendor security advisories
- Review user privileges and access controls
Chain of evidence and sources
OPNsense sürüm 26.1.11 öncesinde openvpn_csc_conf_write() fonksiyonu common_name alanındaki path traversal dizilerini normalleştirmez.
CVE-2026-58393 için temel CVSS skoru 5.9 olarak belirlenmiştir.
Show the technical text from the sources
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.
CVSS vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L
CWE: CWE-22
Explanation produced with the local gemini-flash-lite-latest model. Numerical metrics and the KEV, patch and exploit statuses are not determined by AI.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-58393 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
| ID | VENDOR | PRODUCT | ACTION |
|---|---|---|---|
| 1 | opnsense | core | View |
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 5.9 | CVSS V31 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L | NVD |
| 5.9 | CVSS V3_1 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L | CVE CNA |
Patch and Remediation Guide
Solution & Remediation Advisory
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Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-58393 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-58393 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
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