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FortiproxyApplication · Fortinet

CVE-2023-36639

HIGH · 8.8 CVSS v3.1 Published 2023-12-13
Fix available
A fix is available. Upgrade to after 7.2.4 or later.
See remediation →
94/100
Remediation priority · Urgent
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
A use of externally-controlled format string in Fortinet FortiProxy versions 7.2.0 through 7.2.4, 7.0.0 through 7.0.10, FortiOS versions 7.4.0, 7.2.0 through 7.2.4, 7.0.0 through 7.0.11, 6.4.0 through 6.4.12, 6.2.0 through 6.2.15, 6.0.0 through 6.0.17, FortiPAM versions 1.0.0 through 1.0.3 allows attacker to execute unauthorized code or commands via specially crafted API requests.

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

This is a format string injection vulnerability in Fortinet FortiProxy, FortiOS, and FortiPAM where specially crafted API requests containing user-controlled format specifiers are processed without proper sanitization. An attacker can exploit this to read/write arbitrary memory locations and potentially achieve remote code execution.

MitigationApply the vendor-released patches to upgrade affected FortiProxy, FortiOS, and FortiPAM installations to patched versions. If immediate patching is not possible, restrict API access through network segmentation or a WAF as a temporary compensating control.

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
FortiproxyApplication
Affected:>= 7.0.0, <= 7.0.10>= 7.2.0, <= 7.2.4
FortiosOperating system
Affected:>= 6.0.0, <= 6.0.17>= 6.2.0, <= 6.2.15>= 6.4.0, <= 6.4.12>= 7.0.0, <= 7.0.11>= 7.2.0, <= 7.2.4= 7.4.0
FortipamOperating system
Affected:>= 1.0.0, <= 1.0.3= 1.1.0

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
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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 the Fortinet product
    Determine which Fortinet product is running in your environment: FortiProxy, FortiOS, or FortiPAM. This can be done via the web UI dashboard, CLI command 'get system status', or by checking the support ticket/asset inventory.
    Affected if The product is FortiProxy, FortiOS, or FortiPAM
  2. Determine the installed version
    Run the CLI command 'get system status' or check the web UI under Dashboard > System Information > Firmware Version. Compare the version number against the affected ranges provided: FortiProxy 7.0.0-7.0.10, 7.2.0-7.2.4; FortiOS 6.0.0-6.0.17, 6.2.0-6.2.15, 6.4.0-6.4.12, 7.0.0-7.0.11, 7.2.0-7.2.4, 7.4.0; FortiPAM 1.0.0-1.0.3, 1.1.0.
    Affected if The installed version falls within any of the listed affected version ranges
  3. Check if REST API is enabled
    In FortiOS/FortiProxy, run 'get system global' and look for 'set rest-api-port' or check via web UI under System > Administration > Administrators to see if REST API access is configured. In FortiPAM, check under API Users or REST API settings.
    Affected if The REST API interface is enabled and accessible (even on a non-default port)
  4. Verify API access exposure
    Check the firewall policy and interface settings to determine if the REST API is exposed to untrusted networks. Use 'show system interface' and review firewall policies with 'get firewall policy' to identify if API port (default 443) is accessible from WAN or untrusted segments.
    Affected if The API is reachable from outside the trusted management network or from untrusted interfaces

You are affected if your FortiProxy, FortiOS, or FortiPAM version matches one of the affected ranges AND the REST API feature is enabled and accessible, regardless of exposure scope.

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 a release after 7.2.4
Interim mitigation

Apply the vendor-released patches to upgrade affected FortiProxy, FortiOS, and FortiPAM installations to patched versions. If immediate patching is not possible, restrict API access through network segmentation or a WAF as a temporary compensating control.

Recommended fix High confidence

FortiProxy: 7.0.11+ or 7.2.5+ | FortiOS: 6.0.18+, 6.2.16+, 6.4.13+, 7.0.12+, 7.2.5+, or 7.4.1+ | FortiPAM: 1.1.1+

  1. 1. Identify the current Fortinet product (FortiProxy, FortiOS, or FortiPAM) and its exact version using the CLI command 'get system status' or through the web UI dashboard.
  2. 2. For FortiProxy: If running 7.0.0-7.0.10, upgrade to 7.0.11 or later. If running 7.2.0-7.2.4, upgrade to 7.2.5 or later.
  3. 3. For FortiOS: If running 6.0.x, upgrade to 6.0.18 or later. If running 6.2.x, upgrade to 6.2.16 or later. If running 6.4.x, upgrade to 6.4.13 or later. If running 7.0.x, upgrade to 7.0.12 or later. If running 7.2.x, upgrade to 7.2.5 or later. If running 7.4.0, upgrade to 7.4.1 or later.
  4. 4. For FortiPAM: If running 1.0.0-1.0.3 or 1.1.0, upgrade to 1.1.1 or later.
  5. 5. Download the firmware from the Fortinet Support Portal (https://support.fortinet.com) and upload it via the FortiGate/FortiProxy web UI under System > Firmware, or use the CLI command 'execute firmware upgrade' with the firmware file path.
  6. 6. After upgrade, verify the new version is installed using 'get system status' and confirm the CVE is resolved in the FortiGuard release notes.
Caveat Review Fortinet release notes for the target version as minor releases may introduce configuration or behavioral changes; test in a non-production environment first.

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

Fix this in Fortiproxy 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-2023-36639 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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