# CVE-2023-47537 — Fortinet FortiOS

> As of 2026-01-14, CVE-2023-47537 is a MEDIUM-severity vulnerability in Fortinet FortiOS, CVSS v3.1 4.4, EPSS 0.2% (10.8th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2023-47537, most recently “Multiple Fortinet FortiOS Vulnerabilities (incl. CVE-2024-23113) Affect Siemens RUGGEDCOM APE1808 via Bundled Fortinet NGFW < V7.4.3 (SSA-832273)”.

**Last updated:** 2026-01-14

## What is CVE-2023-47537?

An improper certificate validation vulnerability in Fortinet FortiOS 7.4.0 through 7.4.1, FortiOS 7.2.0 through 7.2.6, FortiOS 7.0.0 through 7.0.15, FortiOS 6.4 all versions allows a remote and unauthenticated attacker to perform a Man-in-the-Middle attack on the FortiLink communication channel between the FortiOS device and FortiSwitch.

The record classifies CVE-2023-47537 under weakness class [CWE-295](https://intel.threadlinqs.com/cwe/CWE-295). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 981 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 4.4 — MEDIUM (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:X/RC:X`)
- **EPSS (FIRST):** 0.2% probability of exploitation in the next 30 days, higher than 10.8% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4.6/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2024-02-15, last modified 2026-01-14

## Is CVE-2023-47537 being exploited?

Weaponised exploit code for CVE-2023-47537 is publicly available. 1 public proof-of-concept repository is tracked for this identifier. It currently carries a trending score of 16 in the Threadlinqs vulnerability feed.

- [trickest/cve](https://github.com/trickest/cve/blob/main/2023/CVE-2023-47537.md) (trickest)

## Affected products and versions

- [Fortinet](https://intel.threadlinqs.com/vendors/fortinet): FortiOS

## How to fix CVE-2023-47537

No vendor patch reference has been recorded for CVE-2023-47537 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2023-47537

1 tracked threat in the Threadlinqs corpus references CVE-2023-47537, either in the campaign’s CVE list or as an indicator on the campaign record.

- [Multiple Fortinet FortiOS Vulnerabilities (incl. CVE-2024-23113) Affect Siemens RUGGEDCOM APE1808 via Bundled Fortinet NGFW < V7.4.3 (SSA-832273)](https://intel.threadlinqs.com/threat/TL-2026-2489) — CRITICAL · 2026-09-13

## Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-10-10.

**Other references**

- [fortiguard.com](https://fortiguard.com/psirt/FG-IR-23-301)

Canonical: https://intel.threadlinqs.com/cve/CVE-2023-47537
Full detection coverage and IOCs for threats exploiting CVE-2023-47537 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp