---
title: "CVE-2018-13383: Out-of-bounds Write | CubePath"
description: "A heap buffer overflow in Fortinet FortiOS 6.0.0 through 6.0.4, 5.6.0 through 5.6.10, 5.4.0 through 5.4.12, 5.2.14 and earlier and FortiProxy 2.0.0…"
language: en
source: https://cubepath.com/security/cve/CVE-2018-13383
---

# CVE-2018-13383: Out-of-bounds Write | CubePath

## Description

A heap buffer overflow in Fortinet FortiOS 6.0.0 through 6.0.4, 5.6.0 through 5.6.10, 5.4.0 through 5.4.12, 5.2.14 and earlier and FortiProxy 2.0.0, 1.2.8 and earlier in the SSL VPN web portal may cause the SSL VPN web service termination for logged in users due to a failure to properly handle javascript href data when proxying webpages.

Official description from the CVE record, published by fortinet. Copyright © 1999-2026 The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CVE license. [View the record on cve.org](https://www.cve.org/CVERecord?id=CVE-2018-13383)

## Key data

### CVSS 3.1 Medium 4.3

Score published by fortinet in the CVE record.

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

| Metric                 | Value     | What it means                                                                       |
| ---------------------- | --------- | ----------------------------------------------------------------------------------- |
| Attack vector          | Network   | The vulnerable component can be reached over a network, possibly from the Internet. |
| Attack complexity      | Low       | No special conditions are needed. The attack can be repeated at will.               |
| Privileges required    | Low       | A basic user account is needed.                                                     |
| User interaction       | None      | No action from any user is needed.                                                  |
| Scope                  | Unchanged | The impact stays within the vulnerable component.                                   |
| Confidentiality impact | None      | No effect on the secrecy of data.                                                   |
| Integrity impact       | None      | No effect on the trustworthiness of data.                                           |
| Availability impact    | Low       | Limited effect on availability.                                                     |

CVSS is owned and managed by FIRST.Org, Inc. (FIRST) and is used by permission. Each CVSS score on this site is shown together with its vector string, as published in the CVE record by the source named next to it. Learn more at [first.org/cvss](https://www.first.org/cvss/) .

### EPSS

Exploit Prediction Scoring System by FIRST: an estimate of the probability that exploitation activity will be observed in the next 30 days.

Score

0.30670 (30.7% probability)

Percentile

98.3%

Scores of

Nov 10, 2026

Model

v2026.06.15

### CISA Known Exploited Vulnerabilities

This CVE is listed in the CISA KEV catalog.

Name in the catalog

Fortinet FortiOS and FortiProxy Out-of-bounds Write

Added to the catalog

Jan 10, 2022

Federal due date

Jul 10, 2022

Ransomware campaigns

Known use

### CISA assessment as of Oct 23, 2024

Stakeholder-Specific Vulnerability Categorization (SSVC) decision points added by CISA.

Exploitation

Recorded by CISA as active

Automatable

no

Technical impact

partial

### Weakness (CWE)

CWE catalog version 5.0.

CWE names: Copyright © 2006-2026, The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CWE license.

- [CWE-787](https://cwe.mitre.org/data/definitions/787.html) Out-of-bounds Write

## Affected products

Products listed in the CVE record, as the CNA published them.

- Fortinet FortiOS and FortiProxy

  - affected: FortiOS 6.0.0 through 6.0.4, 5.6.0 through 5.6.10, 5.4.0 through 5.4.12, 5.2.14 and earlier, FortiProxy 2.0.0, 1.2.8 and earlier

## References

Links listed in the CVE record. They lead to other sites, which CubePath does not control.

- [fortiguard.com/advisory/FG-IR-18-388](https://fortiguard.com/advisory/FG-IR-18-388)
- [fortiguard.com/advisory/FG-IR-20-229](https://fortiguard.com/advisory/FG-IR-20-229)

## Timeline

1. ID reserved Jul 6, 2018
2. Record published May 29, 2019
3. Added to CISA KEV Jan 10, 2022
4. Record last updated Oct 21, 2025

## Look up another CVE

## About CubePath

CubePath is a cloud provider with data centers in Europe and the United States. It offers VPS, bare metal servers and DDoS protection.

[Cloud VPS](https://cubepath.com/vps) [DDoS protection](https://cubepath.com/ddos-protection)

Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 19:34 UTC. [Sources and licenses](https://cubepath.com/security/cve/legal)