Vulnerability-Lookup

GHSA-4QQR-VV2Q-CMR5

Vulnerability from github – Published: 2026-06-16 21:00 – Updated: 2026-06-16 21:00

Summary

Crawl4AI: SSRF filter bypass in Docker server via IPv6 transition forms (NAT64 / 6to4 / unspecified / v4-mapped)

Details

Summary

The Docker API server's SSRF protection (validate_webhook_url / validate_url_destination in deploy/docker/utils.py) used an explicit IPv4/IPv6 CIDR blocklist that missed several address families. An attacker could reach internal services and cloud metadata endpoints (e.g. 169.254.169.254) despite the filter by encoding an internal IPv4 address inside an IPv6 transition form, or by using the IPv6 unspecified address.

Because the Docker API is unauthenticated by default (jwt_enabled: false), no credentials are required.

Affected paths

The blocklist was applied to crawl URLs (POST /crawl, /md, /html, /screenshot, /pdf, /execute_js) and webhook URLs (/crawl/job, /llm/job). All shared the same incomplete check.

Bypasses

The following all resolve to (or route to) blocked internal addresses but were NOT caught: - IPv6 unspecified :: - NAT64 64:ff9b::a9fe:a9fe (embeds 169.254.169.254) - 6to4 2002:a9fe:a9fe:: (embeds 169.254.169.254) - IPv4-mapped ::ffff:169.254.169.254 - IPv4-compatible ::a9fe:a9fe

The error message also echoed the resolved internal IP, acting as a minor DNS/oracle leak.

Impact

Server-Side Request Forgery: an unauthenticated attacker can make the server fetch internal-network URLs and cloud instance-metadata endpoints, potentially exposing internal services and cloud credentials.

Fix

The blocklist is replaced by a single rule: reject any resolved IP where not ip.is_global, evaluated on the address AND every embedded IPv4 transition form (v4-mapped, NAT64 64:ff9b::/96, 6to4 2002::/16, v4-compat ::/96). Error messages are now opaque and no longer echo the resolved IP.

Workarounds

Upgrade to the patched version.
Enable authentication (CRAWL4AI_API_TOKEN).
Restrict the container's outbound network access (egress firewall / no metadata route).

Credits

Internal security audit (Crawl4AI maintainers).

Severity

7.5 (High)


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

Show details on source website

JSON

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.8.7"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "crawl4ai"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.8.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-53754"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-16T21:00:04Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\n\nThe Docker API server\u0027s SSRF protection (`validate_webhook_url` / `validate_url_destination` in `deploy/docker/utils.py`) used an explicit IPv4/IPv6 CIDR blocklist that missed several address families. An attacker could reach internal services and cloud metadata endpoints (e.g. `169.254.169.254`) despite the filter by encoding an internal IPv4 address inside an IPv6 transition form, or by using the IPv6 unspecified address.\n\nBecause the Docker API is unauthenticated by default (`jwt_enabled: false`), no credentials are required.\n\n### Affected paths\n\nThe blocklist was applied to crawl URLs (`POST /crawl`, `/md`, `/html`, `/screenshot`, `/pdf`, `/execute_js`) and webhook URLs (`/crawl/job`, `/llm/job`). All shared the same incomplete check.\n\n### Bypasses\n\nThe following all resolve to (or route to) blocked internal addresses but were NOT caught:\n- IPv6 unspecified `::`\n- NAT64 `64:ff9b::a9fe:a9fe` (embeds `169.254.169.254`)\n- 6to4 `2002:a9fe:a9fe::` (embeds `169.254.169.254`)\n- IPv4-mapped `::ffff:169.254.169.254`\n- IPv4-compatible `::a9fe:a9fe`\n\nThe error message also echoed the resolved internal IP, acting as a minor DNS/oracle leak.\n\n### Impact\n\nServer-Side Request Forgery: an unauthenticated attacker can make the server fetch internal-network URLs and cloud instance-metadata endpoints, potentially exposing internal services and cloud credentials.\n\n### Fix\n\nThe blocklist is replaced by a single rule: reject any resolved IP where `not ip.is_global`, evaluated on the address AND every embedded IPv4 transition form (v4-mapped, NAT64 `64:ff9b::/96`, 6to4 `2002::/16`, v4-compat `::/96`). Error messages are now opaque and no longer echo the resolved IP.\n\n### Workarounds\n\n- Upgrade to the patched version.\n- Enable authentication (`CRAWL4AI_API_TOKEN`).\n- Restrict the container\u0027s outbound network access (egress firewall / no metadata route).\n\n### Credits\n\nInternal security audit (Crawl4AI maintainers).",
  "id": "GHSA-4qqr-vv2q-cmr5",
  "modified": "2026-06-16T21:00:04Z",
  "published": "2026-06-16T21:00:04Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/unclecode/crawl4ai/security/advisories/GHSA-4qqr-vv2q-cmr5"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/unclecode/crawl4ai"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Crawl4AI: SSRF filter bypass in Docker server via IPv6 transition forms (NAT64 / 6to4 / unspecified / v4-mapped)"
}

CVE-2026-53754 (GCVE-0-2026-53754)

Vulnerability from cvelistv5 – Published: 2026-06-23 18:16 – Updated: 2026-06-23 18:54

Title

Crawl4AI: SSRF filter bypass in Docker server via IPv6 transition forms (NAT64 / 6to4 / unspecified / v4-mapped)

Summary

Crawl4AI is an open-source LLM friendly web crawler & scraper. Prior to 0.8.8, the Docker API server's SSRF protection (validate_webhook_url / validate_url_destination in deploy/docker/utils.py) used an explicit IPv4/IPv6 CIDR blocklist that missed several address families. An attacker could reach internal services and cloud metadata endpoints (e.g. 169.254.169.254) despite the filter by encoding an internal IPv4 address inside an IPv6 transition form, or by using the IPv6 unspecified address. Because the Docker API is unauthenticated by default (jwt_enabled: false), no credentials are required. This vulnerability is fixed in 0.8.8.

Severity

7.5 (High)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-918 - Server-Side Request Forgery (SSRF)

Assigner

GitHub_M

References

1 reference

URL	Tags
https://github.com/unclecode/crawl4ai/security/ad…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
unclecode	crawl4ai	Affected: < 0.8.8

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-53754",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-23T18:54:04.711472Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-23T18:54:14.891Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "crawl4ai",
          "vendor": "unclecode",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.8.8"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Crawl4AI is an open-source LLM friendly web crawler \u0026 scraper. Prior to 0.8.8, the Docker API server\u0027s SSRF protection (validate_webhook_url / validate_url_destination in deploy/docker/utils.py) used an explicit IPv4/IPv6 CIDR blocklist that missed several address families. An attacker could reach internal services and cloud metadata endpoints (e.g. 169.254.169.254) despite the filter by encoding an internal IPv4 address inside an IPv6 transition form, or by using the IPv6 unspecified address. Because the Docker API is unauthenticated by default (jwt_enabled: false), no credentials are required. This vulnerability is fixed in 0.8.8."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-918",
              "description": "CWE-918: Server-Side Request Forgery (SSRF)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-23T18:16:34.260Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/unclecode/crawl4ai/security/advisories/GHSA-4qqr-vv2q-cmr5",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/unclecode/crawl4ai/security/advisories/GHSA-4qqr-vv2q-cmr5"
        }
      ],
      "source": {
        "advisory": "GHSA-4qqr-vv2q-cmr5",
        "discovery": "UNKNOWN"
      },
      "title": "Crawl4AI: SSRF filter bypass in Docker server via IPv6 transition forms (NAT64 / 6to4 / unspecified / v4-mapped)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-53754",
    "datePublished": "2026-06-23T18:16:34.260Z",
    "dateReserved": "2026-06-10T17:48:40.546Z",
    "dateUpdated": "2026-06-23T18:54:14.891Z",
    "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-4QQR-VV2Q-CMR5

Summary

Affected paths

Bypasses

Impact

Fix

Workarounds

Credits

CVE-2026-53754 (GCVE-0-2026-53754)

Tags

Sightings

Nomenclature