Vulnerability-Lookup

FKIE_CVE-2026-42511

Vulnerability from fkie_nvd - Published: 2026-04-30 07:16 - Updated: 2026-06-17 10:47

Severity

8.1 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

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.

References

	URL	Tags
	secteam@freebsd.org	https://security.freebsd.org/advisories/FreeBSD-SA-26:12.dhclient.asc	Vendor Advisory

Impacted products

Vendor	Product	Version
freebsd	freebsd	13.5
freebsd	freebsd	13.5
freebsd	freebsd	13.5
freebsd	freebsd	13.5
freebsd	freebsd	13.5
freebsd	freebsd	13.5
freebsd	freebsd	13.5
freebsd	freebsd	13.5
freebsd	freebsd	13.5
freebsd	freebsd	13.5
freebsd	freebsd	13.5
freebsd	freebsd	13.5
freebsd	freebsd	13.5
freebsd	freebsd	13.5
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.4
freebsd	freebsd	14.4
freebsd	freebsd	14.4
freebsd	freebsd	14.4
freebsd	freebsd	15.0
freebsd	freebsd	15.0
freebsd	freebsd	15.0
freebsd	freebsd	15.0
freebsd	freebsd	15.0
freebsd	freebsd	15.0
freebsd	freebsd	15.0

JSON

To clipboard

{
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      "affectedData": [
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          "modules": [
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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.\n\nA rogue DHCP server may be able to execute arbirary code as root on a system running dhclient."
    }
  ],
  "id": "CVE-2026-42511",
  "lastModified": "2026-06-17T10:47:57.713",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.1,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
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        "impactScore": 5.9,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
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    "ssvcV203": [
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        "ssvcData": {
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          "options": [
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            {
              "technicalImpact": "total"
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          "role": "CISA Coordinator",
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          "version": "2.0.3"
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  "published": "2026-04-30T07:16:37.290",
  "references": [
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      "source": "secteam@freebsd.org",
      "tags": [
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      "url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:12.dhclient.asc"
    }
  ],
  "sourceIdentifier": "secteam@freebsd.org",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-149"
        }
      ],
      "source": "secteam@freebsd.org",
      "type": "Secondary"
    }
  ]
}

CVE-2026-42511 (GCVE-0-2026-42511)

Vulnerability from cvelistv5 – Published: 2026-04-30 06:56 – Updated: 2026-05-01 15:25

Title

Remote code execution via malicious DHCP options

Summary

Severity

8.1 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-05-01 03:55 UTC

CWE

CWE-149 - Improper Neutralization of Quoting Syntax

Assigner

freebsd mitre root

References

1 reference

URL	Tags
https://security.freebsd.org/advisories/FreeBSD-S…	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
FreeBSD	FreeBSD	Affected: 15.0-RELEASE , < p7 (release) Affected: 14.4-RELEASE , < p3 (release) Affected: 14.3-RELEASE , < p12 (release) Affected: 13.5-RELEASE , < p13 (release)

Date Public

2026-04-29 19:00

Credits

Joshua Rogers of AISLE Research Team

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "HIGH",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 8.1,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-42511",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-01T03:55:55.336127Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-01T15:25:37.800Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "modules": [
            "dhclient"
          ],
          "product": "FreeBSD",
          "vendor": "FreeBSD",
          "versions": [
            {
              "lessThan": "p7",
              "status": "affected",
              "version": "15.0-RELEASE",
              "versionType": "release"
            },
            {
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              "status": "affected",
              "version": "14.4-RELEASE",
              "versionType": "release"
            },
            {
              "lessThan": "p12",
              "status": "affected",
              "version": "14.3-RELEASE",
              "versionType": "release"
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              "lessThan": "p13",
              "status": "affected",
              "version": "13.5-RELEASE",
              "versionType": "release"
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        }
      ],
      "credits": [
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          "lang": "en",
          "type": "finder",
          "value": "Joshua Rogers of AISLE Research Team"
        }
      ],
      "datePublic": "2026-04-29T19:00:00.000Z",
      "descriptions": [
        {
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          "value": "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.\n\nA rogue DHCP server may be able to execute arbirary code as root on a system running dhclient."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-149",
              "description": "CWE-149: Improper Neutralization of Quoting Syntax",
              "lang": "en",
              "type": "CWE"
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      "providerMetadata": {
        "dateUpdated": "2026-04-30T06:56:36.929Z",
        "orgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
        "shortName": "freebsd"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:12.dhclient.asc"
        }
      ],
      "title": "Remote code execution via malicious DHCP options",
      "x_generator": {
        "engine": "cvelib 1.8.0"
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  },
  "cveMetadata": {
    "assignerOrgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
    "assignerShortName": "freebsd",
    "cveId": "CVE-2026-42511",
    "datePublished": "2026-04-30T06:56:36.929Z",
    "dateReserved": "2026-04-28T05:31:44.956Z",
    "dateUpdated": "2026-05-01T15:25:37.800Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.