CVE-2026-45158

Critical

Published: 13 May 2026

Published

13 May 2026

Modified

15 May 2026

KEV Added

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Patch

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CVSS Score v3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

EPSS Score 0.0053 40.9th percentile

Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2026-45158 is a critical-severity Argument Injection (CWE-88) vulnerability in Opnsense Opnsense. Its CVSS base score is 9.1 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 40.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2026-30202

Vulnerability details

OPNsense is a FreeBSD based firewall and routing platform. Prior to 26.1.8, unsanitized user input is passed to the DHCP configuration of the configured interface, which is processed by a shell script, allowing remote code execution as root on the…

underlying operating system. This vulnerability is fixed in 26.1.8.

CWE(s): CWE-88

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1059.004 Unix Shell Execution

Adversaries may abuse Unix shell commands and scripts for execution.

attack.mitre.org →

Why these techniques?

Unsanitized input to DHCP config processed by shell script enables RCE as root on public-facing firewall (T1190); execution occurs via Unix shell (T1059.004).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0