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

CVE-2026-4528

HIGH · 7.3 CVSS v3.1 Published 2026-03-21
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
82/100
Remediation priority · High
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
A vulnerability was determined in trueleaf ApiFlow 0.9.7. The impacted element is the function validateUrlSecurity of the file packages/server/src/service/proxy/http_proxy.service.ts of the component URL Validation Handler. This manipulation causes server-side request forgery. Remote exploitation of the attack is possible. The exploit has been publicly disclosed and may be utilized.

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 · moderate confidence

TrueLeaf ApiFlow 0.9.7 contains a server-side request forgery (SSRF) vulnerability in the validateUrlSecurity function within the HTTP proxy service's URL validation handler. Attackers can exploit this to make the server perform requests to internal resources or arbitrary external endpoints by providing malicious URLs that bypass inadequate validation checks.

MitigationImplement robust URL validation that blocks requests to private/internal IP ranges (including localhost/127.0.0.1), internal network addresses, and potentially dangerous protocols. Additionally, implement allowlist-based URL filtering where only explicitly permitted domains/patterns can be accessed.

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
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

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

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. Confirm TrueLeaf ApiFlow is installed
    Locate the ApiFlow installation directory and check for the presence of ApiFlow executables or services. Common locations may include /opt/apiflow, /usr/local/apiflow, or check system services for 'apiflow' or 'truleaf' processes.
    Affected if TrueLeaf ApiFlow software is not present on the system
  2. Identify installed ApiFlow version
    Run version command or check version file: Look for --version flag, check README, version.txt, or the binary metadata for the exact version number.
    Affected if Installed version is 0.9.7 exactly (this specific version contains the vulnerability)
  3. Determine if HTTP proxy service is enabled
    Examine ApiFlow configuration files for proxy-related settings. Look for sections like 'proxy', 'urlvalidation', 'httpproxy', or similar. Check if the proxy service is listed as enabled or active in the main configuration.
    Affected if HTTP proxy service is enabled and the validateUrlSecurity function is in use
  4. Inspect URL validation configuration
    Review the validateUrlSecurity function configuration or URL validation rules in the ApiFlow config files. Check for whitelist/blacklist settings related to URL handling.
    Affected if URL validation is present but does not explicitly block private IP ranges (127.0.0.1, 10.x.x.x, 192.168.x.x), internal network addresses, or dangerous protocols (gopher, file, etc.)
  5. Test for SSRF susceptibility (if authorized)
    If you have authorization, send a request through the proxy to an internal endpoint like http://127.0.0.1:port or http://localhost to see if the server performs the request.
    Affected if The proxy successfully makes requests to localhost or internal resources, indicating the validation can be bypassed

A system is affected if TrueLeaf ApiFlow version 0.9.7 is installed with the HTTP proxy service enabled and the validateUrlSecurity function lacks proper blocking of internal/private IP addresses and dangerous URL protocols.

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

Implement robust URL validation that blocks requests to private/internal IP ranges (including localhost/127.0.0.1), internal network addresses, and potentially dangerous protocols. Additionally, implement allowlist-based URL filtering where only explicitly permitted domains/patterns can be accessed.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2026-4528 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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