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

CVE-2026-42345

HIGH · 7.7 CVSS v3.1 Published 2026-05-08
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
83/100
Remediation priority · High
Remotely reachable 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
FastGPT is an AI Agent building platform. In versions 4.14.11 and prior, FastGPT's isInternalAddress() function in packages/service/common/system/utils.ts blocks cloud metadata endpoints using a fullUrl.startsWith() check against a hardcoded list. This check can be bypassed using at least 7 different URL encoding techniques, all of which resolve to the same cloud metadata service but do not match the blocklist patterns. Additionally, the broader private IP check (isInternalIPv4/isInternalIPv6) is disabled by default because CHECK_INTERNAL_IP defaults to false (not 'true'), so these bypasses reach the metadata endpoint without any further validation. At time of publication, there are no publicly available patches.

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

FastGPT's isInternalAddress() function uses a weak fullUrl.startsWith() check against a hardcoded blocklist to prevent access to cloud metadata services (e.g., 169.254.169.254). This check can be bypassed using 7+ URL encoding techniques that resolve to the same metadata endpoint but don't match the blocklist patterns. Additionally, the broader CHECK_INTERNAL_IP validation is disabled by default (defaults to false), allowing these bypasses to reach the metadata service without further IP validation. This is an SSRF vulnerability enabling potential cloud metadata exposure.

MitigationEnable CHECK_INTERNAL_IP=true in configuration to activate robust private IP validation, and implement proper URL parsing that validates the resolved IP address rather than relying on string prefix matching against a blocklist.

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

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
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/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. Identify FastGPT version
    Locate the FastGPT version in package.json, docker-compose.yml, or by querying the running service's /api/manage version endpoint if available
    Affected if Version is 4.14.11 or lower
  2. Verify CHECK_INTERNAL_IP configuration
    Search configuration files (config.yaml, .env, or environment variables) for the CHECK_INTERNAL_IP setting
    Affected if CHECK_INTERNAL_IP is not set to 'true', is set to 'false', or is missing (defaults to false, enabling the bypass)
  3. Inspect isInternalAddress implementation
    Examine the source code or runtime behavior of the isInternalAddress() function in the FastGPT codebase for the use of fullUrl.startsWith() with a blocklist approach
    Affected if The function uses startsWith() against a blocklist rather than proper URL normalization and allowlist validation
  4. Confirm metadata endpoint accessibility
    Attempt an internal network request from the FastGPT server to 169.254.169.254 (cloud metadata IP) using various URL encodings to test if the SSRF is exploitable
    Affected if Requests to metadata endpoints succeed or return valid responses from cloud metadata services

A user is affected if running FastGPT version 4.14.11 or prior with CHECK_INTERNAL_IP not explicitly set to true, combined with the weak startsWith() blocklist validation that can be bypassed via URL encoding to reach cloud metadata endpoints.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Enable CHECK_INTERNAL_IP=true in configuration to activate robust private IP validation, and implement proper URL parsing that validates the resolved IP address rather than relying on string prefix matching against a blocklist.

Have this fixed 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
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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-2026-42345 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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