CVE-2026-45158: OPNsense is a FreeBSD based firewall and routing platform

Q: How do I fix CVE-2026-45158?

opnsense: upgrade to 26.1.8. Exact commands for each OS are on this page.

Q: Is CVE-2026-45158 being exploited?

CVE-2026-45158 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-45158 affect?

CVE-2026-45158 affects opnsense. Severity is critical (CVSS 9.1). 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

Q: How urgent is CVE-2026-45158?

Priority 43/100. Critical severity

This month

CRITICAL 9.1UPGRADE

CVE-2026-45158 is a critical-severity flaw (CVSS 9.1) affecting opnsense. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	High
User interaction	None
EPSS exploit chance	0.5% (top 55%)
CISA exploited list	No
Weakness	CWE-88
Published	2026-05-13
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: opnsense

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-13 22:16 UTCPublished CVE record published
2026-10-26 14:10 UTCUpdated Record last modified

opnsense opnsense UPGRADE

Affected: < 26.1.8

Fixed in: 26.1.8

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy opnsense || rpm -q opnsense || opnsense --version

2. UPGRADE to 26.1.8 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade opnsense

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade opnsense

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-45158?

opnsense: upgrade to 26.1.8. Exact commands for each OS are on this page.

Is CVE-2026-45158 being exploited?

CVE-2026-45158 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-45158 affect?

CVE-2026-45158 affects opnsense. Severity is critical (CVSS 9.1). 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

How urgent is CVE-2026-45158?

Priority 43/100. Critical severity

Software pages

pfSense and OPNsense vulnerabilities

Related CVEs

CVE-2026-44194 CRITICAL 9.1 UPGRADE OPNsense is a FreeBSD based firewall and routing platform
CVE-2026-44193 CRITICAL 9.1 UPGRADE OPNsense is a FreeBSD based firewall and routing platform
CVE-2026-44195 MEDIUM 5.3 UPGRADE OPNsense is a FreeBSD based firewall and routing platform

References

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