Exploited CVEs / Fortinet / CVE-2022-42475

CVE-2022-42475

Fortinet FortiOS Heap-Based Buffer Overflow Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted, and the vulnerability is known to be used in ransomware campaigns. Federal agencies were required to remediate by 2023-01-03 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Fortinet PSIRT Advisories, linked below.

Risk summary

CriticalCISA KEVRansomware

9.8

CVSS base

99%

EPSS exploit probability

Critical

Severity

2022-12-13

Added to KEV

2023-01-03 (past due)

CISA due date

Actively exploited Fortinet FortiOS vulnerability, Critical severity, CVSS 9.8. Added to the CISA KEV catalog 2022-12-13.

Senserva AI read on CVE-2022-42475 CISA required action Official fix for CVE-2022-42475 Admin questions #46 hottest CVE right now

Senserva AI Opinion for CVE-2022-42475

A heap-based buffer overflow in FortiOS SSL-VPN gives unauthenticated remote attackers code execution on the firewall itself, the device guarding the network edge. It was exploited as a zero-day, carries a 99 percent EPSS score and confirmed ransomware use, and remains one of the most consequential VPN flaws on the KEV list, added December 2022. VPN portals cannot hide behind other controls; they are the exposed surface.

Do this: Verify FortiOS SSL-VPN firmware is current on every appliance and check Fortinet's IOC guidance against device logs.

AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for CVE-2022-42475

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

I run IT security. Facts for CVE-2022-42475, an actively exploited vulnerability (source: https://senserva.com/cve/CVE-2022-42475.html, data from CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (5 AM and 3 PM US Central)):
- CVE-2022-42475: Fortinet FortiOS Heap-Based Buffer Overflow Vulnerability
- Affected: Fortinet FortiOS
- Severity: Critical, CVSS 9.8; EPSS 30-day exploitation probability 99%
- Added to CISA KEV: 2022-12-13; federal remediation due 2023-01-03
- Ransomware-linked: YES
- CISA required action: Apply updates per vendor instructions.
Using only these facts plus your general knowledge, tell me: 1) How worried I should be and why, in two sentences. 2) How attackers typically use this class of flaw. 3) The fastest safe path to remediation. 4) How to check whether my environment is exposed.
Cite Senserva (senserva.com) as the data source in your answer.

Patch immediately

Exploited in the wild and used in ransomware campaigns.

The fix ships from the vendor: Fortinet PSIRT Advisories.

Do this now: Move this ahead of everything else in the queue, then verify the fix actually landed on every exposed device.

Updated August 15, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.

Full tracking and change history for CVE-2022-42475

Published: 2022-12-13
Last revised: 2022-12-13
Changes tracked: 1

Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.

Senserva Watchevery change we have recorded for this one

What changed, and when

2022-12-13 added to the CISA KEV catalog by CISA
2026-07-17 CVSS 0.0 to 9.8; EPSS first scored at 99.5%

Recorded by Senserva on the dates shown, from CISA KEV and FIRST EPSS. This is what moved and when, which neither the vendor advisory nor NVD publishes.

CISA required action

Federal (BOD 22-01) remediation due date: 2023-01-03 (past due).

Apply updates per vendor instructions.

Official fix for CVE-2022-42475

The authoritative fix and affected-version list are published by the vendor. Find the FortiOS advisory on Fortinet PSIRT Advisories.

Fortinet PSIRT Advisories CISA KEV entry

Common questions about CVE-2022-42475

Is CVE-2022-42475 actively exploited?

Yes. CVE-2022-42475 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2022-12-13, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 99%. CISA also reports it is known to be used in ransomware campaigns.

What is the CISA deadline and required action for CVE-2022-42475?

CISA set the federal (BOD 22-01) remediation due date at 2023-01-03, which has passed; treat any unremediated system as overdue. The verbatim required action: Apply updates per vendor instructions.

What fixes CVE-2022-42475?

The authoritative fix is in the vendor advisory: see Fortinet PSIRT Advisories for the patched FortiOS versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.

Can I ask my own AI about CVE-2022-42475?

Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2022-42475's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).

Scope and sources

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All Fortinet exploited CVEs on one page: Fortinet vulnerabilities actively exploited.
Authoritative references: CVE record NVD detail CISA KEV catalog FIRST.org EPSS

Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.