CVE-2026-42511Public exploit

Root code execution via unescaped BOOTP lease field

Published Apr 30, 2026 · Updated Apr 30, 2026

Command injection in FreeBSD 13.5, 14.3, 14.4, and 15.0 allows attackers to execute arbitrary code as root through DHCP. The write_client_lease() function serializes the untrusted BOOTP file field into a quoted lease directive without escaping double quotes; dhclient-script later evaluates the injected medium value. Exploitation requires a rogue DHCP server on the same broadcast domain and a system running dhclient, after which lease renewal or reload triggers root-level shell execution.

CVSS severity8.1
High
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Command injection in FreeBSD 13.5, 14.3, 14.4, and 15.0 allows attackers to execute arbitrary code as root through DHCP. The write_client_lease() function serializes the untrusted BOOTP file field into a quoted lease directive without escaping double quotes; dhclient-script later evaluates the injected medium value. Exploitation requires a rogue DHCP server on the same broadcast domain and a system running dhclient, after which lease renewal or reload triggers root-level shell execution.

The record

CVE
CVE-2026-42511
Published
Apr 30, 2026
Updated
Apr 30, 2026
Vendor
The FreeBSD Project
Product
FreeBSD
Classifications
CWE-149, T1557.003, T1059.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 30, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=13.5-RELEASE <p13
  2. Affected versionversion=14.3-RELEASE <p12
  3. Affected versionversion=14.4-RELEASE <p3
  4. Affected versionversion=15.0-RELEASE <p7

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

The FreeBSD Project · FreeBSDversion=13.5-RELEASE <p13; version=14.3-RELEASE <p12; version=14.4-RELEASE <p3; version=15.0-RELEASE <p7

Published CVSS scores

8.1CISA-ADPCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-149Improper Neutralization of Quoting Syntax
T1557.003DHCP Spoofing
T1059.004Unix Shell

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo