---
id: "CVE-2018-13379"
kind: "vulnerability"
aliases: ["CVE-2018-13379"]
title: "Fortinet FortiOS: Fortinet FortiOS SSL VPN Path Traversal Vulnerability"
severity: "critical"
cvss: 9.8
epss: 0.99999
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Fortinet FortiOS", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "fortinet", "fortios", "infrastructure", "ransomware", "self-hosted", "ssl-vpn"]
not_affected_if: ["no-ssl-vpn-enabled", "not-fortios"]
published_at: "2019-06-04T21:29:00+00:00"
first_seen_at: "2026-10-23T19:11:53+00:00"
updated_at: "2026-10-23T21:57:35+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2018-13379", "first_seen_at": "2026-10-23T19:11:53+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2018-13379", "first_seen_at": "2026-10-23T19:13:44+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2018-13379", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Fortinet FortiOS: Fortinet FortiOS SSL VPN Path Traversal Vulnerability

Fortinet FortiOS SSL VPN web portal has a path traversal flaw that lets an unauthenticated remote attacker download FortiOS system files via crafted HTTP requests. The flaw is on the VPN appliance, and CISA lists it as actively exploited in the wild, with ransomware use noted in the sources.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Fortinet FortiOS affected ? fixed ?

## How to check

Check whether the SSL VPN web portal is reachable from the internet and which FortiOS version is running (unknown for exact affected versions in the sources).

## Fix

Apply the FortiOS update per Fortinet's vendor instructions (fixed version unknown in the sources).
If patching is not immediate, restrict access to the SSL VPN portal (unknown specific setting in the sources).

## Timeline

- 2026-10-23T19:11:53+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2018-13379
- 2026-10-23T19:13:44+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2018-13379
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2018-13379

## From the sources

An Improper Limitation of a Pathname to a Restricted Directory ("Path Traversal") in Fortinet FortiOS 6.0.0 to 6.0.4, 5.6.3 to 5.6.7 and 5.4.6 to 5.4.12 and FortiProxy 2.0.0, 1.2.0 to 1.2.8, 1.1.0 to 1.1.6, 1.0.0 to 1.0.7 under SSL VPN web portal allows an unauthenticated attacker to download system files via special crafted HTTP resource requests.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_