dbcve.org
Crawl4aiApplication · Kidocode

CVE-2026-56266

HIGH · 8.6 CVSS v3.1 Published 2026-06-22
Fix available
A fix is available. Upgrade to 0.8.7 or later.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Crawl4AI before 0.8.7 contains a server-side request forgery vulnerability in the /crawl, /crawl/stream, /md, and /llm endpoints that fetch arbitrary user-supplied URLs without validation. Unauthenticated attackers can bypass the internal-address blocklist using IPv6-mapped IPv4 addresses to reach internal services and cloud metadata endpoints.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Crawl4AI before 0.8.7 has an SSRF vulnerability in /crawl, /crawl/stream, /md, and /llm endpoints where user-supplied URLs are fetched without validation. Attackers bypass internal-address blocklists using IPv6-mapped IPv4 addresses (::ffff:x.x.x.x format) to access internal services and cloud metadata endpoints.

MitigationUpgrade to Crawl4AI 0.8.7 or later, which should include proper URL validation that handles IPv6-mapped addresses and rejects connections to internal/private network ranges and cloud metadata endpoints.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Crawl4aiApplication
Affected:< 0.8.7

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check Crawl4AI version
    Locate the Crawl4AI installation and determine its version number. Common methods: check package.json, requirements.txt, pip show crawl4ai, or the running service version endpoint if available.
    Affected if Version is below 0.8.7
  2. Identify exposed API endpoints
    Review your web server or proxy configuration to determine if the /crawl, /crawl/stream, /md, and /lll endpoints are publicly accessible or accessible from untrusted networks.
    Affected if Any of these endpoints are exposed without authentication or additional filtering layers
  3. Verify URL validation exists
    Inspect the source code or configuration of the Crawl4AI deployment for URL validation logic. Look for checks that parse and validate the URL parameter before fetching.
    Affected if No URL validation is found, or validation does not explicitly handle IPv6-mapped IPv4 addresses (::ffff:x.x.x.x) and internal IP ranges
  4. Check for internal network access controls
    Review network firewall rules, WAF policies, or application-level network restrictions that may (or may not) block requests to internal IP ranges, localhost, or cloud metadata endpoints.
    Affected if No explicit blocks exist for requests to internal addresses, private ranges (10.x.x.x, 192.168.x.x, 172.16-31.x.x), or cloud metadata services (169.254.169.254) when using IPv6-mapped format

A user is affected if they run a Crawl4AI version below 0.8.7 with any of the vulnerable endpoints exposed to users or untrusted networks, and the deployment lacks explicit validation that blocks IPv6-mapped IPv4 addresses targeting internal services.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 0.8.7 or later
Fixed in 0.8.7
Interim mitigation

Upgrade to Crawl4AI 0.8.7 or later, which should include proper URL validation that handles IPv6-mapped addresses and rejects connections to internal/private network ranges and cloud metadata endpoints.

Recommended fix High confidence

Crawl4ai version 0.8.7 or later

  1. 1. Check the current installed version of Crawl4ai using: pip show crawl4ai or the appropriate package manager command
  2. 2. Upgrade Crawl4ai to version 0.8.7 or later using: pip install crawl4ai>=0.8.7
  3. 3. Verify the upgrade was successful by checking the installed version again
  4. 4. Restart the Crawl4ai service to ensure the new version is loaded
  5. 5. Test that the /crawl, /crawl/stream, /md, and /llm endpoints now properly validate URLs and block SSRF attempts including IPv6-mapped IPv4 addresses
Caveat Review release notes for version 0.8.7 to check for any breaking changes in API behavior or configuration

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Crawl4ai Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,224.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-56266 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-56266 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data