Vulnerability-Lookup

GHSA-4CRJ-QC6G-G3XJ

Vulnerability from github – Published: 2026-06-18 15:32 – Updated: 2026-06-18 15:32

Details

Docker Sandboxes (sbx) enforces an HTTP/S-only egress allowlist but does not apply it to DNS resolution: the per-network embedded DNS server forwards any queried name to the host resolver whenever the network is internet-connected, without consulting the policy. A workload inside a sandbox, which the threat model treats as untrusted, can therefore encode data into DNS labels for an attacker-controlled domain and exfiltrate it through a DNS covert channel, bypassing the configured allowlist.

Severity

5.7 (Medium)


                  
                    CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-12039"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-923"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-18T14:17:20Z",
    "severity": "MODERATE"
  },
  "details": "Docker Sandboxes (sbx) enforces an HTTP/S-only egress allowlist but does not apply it to DNS resolution: the per-network embedded DNS server forwards any queried name to the host resolver whenever the network is internet-connected, without consulting the policy. A workload inside a sandbox, which the threat model treats as untrusted, can therefore encode data into DNS labels for an attacker-controlled domain and exfiltrate it through a DNS covert channel, bypassing the configured allowlist.",
  "id": "GHSA-4crj-qc6g-g3xj",
  "modified": "2026-06-18T15:32:02Z",
  "published": "2026-06-18T15:32:02Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-12039"
    },
    {
      "type": "WEB",
      "url": "https://docs.docker.com/ai/sandboxes"
    },
    {
      "type": "WEB",
      "url": "https://github.com/docker/sbx-releases/releases/tag/v0.33.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-12039 (GCVE-0-2026-12039)

Vulnerability from cvelistv5 – Published: 2026-06-18 13:48 – Updated: 2026-06-18 15:00

Title

Docker Sandboxes network egress allowlist bypass via unfiltered DNS resolution

Summary

Severity

5.7 (Medium)


                        
                          CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-923 - Improper Restriction of Communication Channel to Intended Endpoints

Assigner

Docker

References

2 references

URL	Tags
https://docs.docker.com/ai/sandboxes/	product
https://github.com/docker/sbx-releases/releases/t…	release-notes

Impacted products

1 product

Vendor	Product	Version
Docker	Docker Sandboxes	Affected: 0.13.0 , < 0.33.0 (semver)

Credits

Sophie Lemos

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-12039",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-18T15:00:00.773890Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-18T15:00:24.095Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "platforms": [
            "MacOS",
            "Linux",
            "Windows"
          ],
          "product": "Docker Sandboxes",
          "vendor": "Docker",
          "versions": [
            {
              "lessThan": "0.33.0",
              "status": "affected",
              "version": "0.13.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Sophie Lemos"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "Docker Sandboxes (sbx) enforces an HTTP/S-only egress allowlist but does not apply it to DNS resolution: the per-network embedded DNS server forwards any queried name to the host resolver whenever the network is internet-connected, without consulting the policy. A workload inside a sandbox, which the threat model treats as untrusted, can therefore encode data into DNS labels for an attacker-controlled domain and exfiltrate it through a DNS covert channel, bypassing the configured allowlist."
            }
          ],
          "value": "Docker Sandboxes (sbx) enforces an HTTP/S-only egress allowlist but does not apply it to DNS resolution: the per-network embedded DNS server forwards any queried name to the host resolver whenever the network is internet-connected, without consulting the policy. A workload inside a sandbox, which the threat model treats as untrusted, can therefore encode data into DNS labels for an attacker-controlled domain and exfiltrate it through a DNS covert channel, bypassing the configured allowlist."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-554",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-554 Functionality Bypass"
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "LOCAL",
            "baseScore": 5.7,
            "baseSeverity": "MEDIUM",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "LOW",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "NONE",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-923",
              "description": "CWE-923: Improper Restriction of Communication Channel to Intended Endpoints",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-18T13:54:10.585Z",
        "orgId": "686469e6-3ff6-451b-ab8b-cf5b9e89401e",
        "shortName": "Docker"
      },
      "references": [
        {
          "tags": [
            "product"
          ],
          "url": "https://docs.docker.com/ai/sandboxes/"
        },
        {
          "tags": [
            "release-notes"
          ],
          "url": "https://github.com/docker/sbx-releases/releases/tag/v0.33.0"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "title": "Docker Sandboxes network egress allowlist bypass via unfiltered DNS resolution"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "686469e6-3ff6-451b-ab8b-cf5b9e89401e",
    "assignerShortName": "Docker",
    "cveId": "CVE-2026-12039",
    "datePublished": "2026-06-18T13:48:14.682Z",
    "dateReserved": "2026-06-11T19:23:44.967Z",
    "dateUpdated": "2026-06-18T15:00:24.095Z",
    "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.

Action not permitted

GHSA-4CRJ-QC6G-G3XJ

CVE-2026-12039 (GCVE-0-2026-12039)

Tags

Sightings

Nomenclature