FreeBSD up to p2/p6/p11/p12 BOOTP File dhclient.conf quoting syntax

CVSS Meta Temp Score
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CTI Interest Score
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7.7$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as critical, has been found in FreeBSD up to p2/p6/p11/p12. Affected is an unknown function of the file dhclient.conf of the component BOOTP File Handler. Performing a manipulation results in quoting syntax. This vulnerability is cataloged as CVE-2026-42511. It is possible to initiate the attack remotely. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in FreeBSD up to p2/p6/p11/p12. It has been classified as critical. This affects an unknown functionality of the file dhclient.conf of the component BOOTP File Handler. The manipulation with an unknown input leads to a quoting syntax vulnerability. CWE is classifying the issue as CWE-149. Quotes injected into a product can be used to compromise a system. As data are parsed, an injected/absent/duplicate/malformed use of quotes may cause the process to take unexpected actions. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

The BOOTP file field is written to the lease file without escaping embedded double-quotes, allowing injection of arbitrary dhclient.conf directives. When the lease file is subsequently re-parsed by dhclient, e.g., after a system restart, an attacker-controlled field from the lease is passed to dhclient-script(8), which evaluates it. A rogue DHCP server may be able to execute arbirary code as root on a system running dhclient.

The weakness was shared with AISLE Research Team. The advisory is shared at security.freebsd.org. This vulnerability is uniquely identified as CVE-2026-42511 since 04/28/2026. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 05/01/2026).

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-1324). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

  • FreeBSD Project FreeBSD OS

Productinfo

Type

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.1
VulDB Meta Temp Score: 7.7

VulDB Base Score: 8.1
VulDB Temp Score: 7.7
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Quoting syntax
CWE: CWE-149 / CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Timelineinfo

04/28/2026 CVE reserved
04/30/2026 +2 days Advisory disclosed
04/30/2026 +0 days VulDB entry created
05/01/2026 +1 days VulDB entry last update

Sourcesinfo

Product: freebsd.org

Advisory: security.freebsd.org
Organization: AISLE Research Team
Status: Confirmed

CVE: CVE-2026-42511 (🔒)
GCVE (CVE): GCVE-0-2026-42511
GCVE (VulDB): GCVE-100-360249
CERT Bund: WID-SEC-2026-1324 - FreeBSD Project FreeBSD OS: Mehrere Schwachstellen

Entryinfo

Created: 04/30/2026 10:01
Updated: 05/01/2026 03:54
Changes: 04/30/2026 10:01 (55), 05/01/2026 03:54 (7)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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