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Fortinet CVE-2025-55018

MEDIUM
HTTP Request/Response Smuggling (CWE-444)
2026-02-10 psirt@fortinet.com
5.8
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V4 - API and Web Service HTTP request consistency
Impact

CVSS 5.8 (MEDIUM). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: None. Exploitation no authentication required.

Exploit ScenarioDerived

An attacker without authentication could exploit this vulnerability to an unauthenticated attacker to smuggle an unlogged http request through the fire.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

An inconsistent interpretation of http requests ('http request smuggling') vulnerability in Fortinet FortiOS 7.6.0, FortiOS 7.4.0 through 7.4.9, FortiOS 7.2 all versions, FortiOS 7.0 all versions, FortiOS 6.4.3 through 6.4.16 may allow an unauthenticated attacker to smuggle an unlogged http request through the firewall policies via a specially crafted header [CVSS 5.8 MEDIUM]

RemediationAI

Monitor vendor advisories for a patch. Restrict network access to the affected service where possible.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Classified as CWE-444 (HTTP Request/Response Smuggling). Affects Fortios. An inconsistent interpretation of http requests ('http request smuggling') vulnerability in Fortinet FortiOS 7.6.0, FortiOS 7.4.0 through 7.4.9, FortiOS 7.2 all versions, FortiOS 7.0 all versions, FortiOS 6.4.3 through 6.4.16 may allow an unauthenticated attacker to smuggle an unlogged http request through the firewall policies via a specially crafted header

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.8 MEDIUM
AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
None
Integrity
Low
Availability
None

DescriptionCVE.org

An inconsistent interpretation of http requests ('http request smuggling') vulnerability in Fortinet FortiOS 7.6.0, FortiOS 7.4.0 through 7.4.9, FortiOS 7.2 all versions, FortiOS 7.0 all versions, FortiOS 6.4.3 through 6.4.16 may allow an unauthenticated attacker to smuggle an unlogged http request through the firewall policies via a specially crafted header

Executive ViewAI

Why It Matters

CVE-2025-55018 presents moderate security risk rated CVSS 5.8. Exploitation could compromise the security of affected deployments. Organizations should apply vendor updates when available and monitor for exploitation.

Business Impact: Low
Compensating Controls

Apply vendor patch. If patching is delayed: restrict network access and enable monitoring.

Threat Intelligence Overview

EPSS Score
0.1%
Top 84% exploitable
Threat Intel
1
1 source
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.1%
Patch available No
Active threat Yes
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact
Low

Priority Score

39
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +29
PoC: 0
Weaponized: 0
Threat intel: +10
Gov advisory: 0

Attack Technique

HTTP request smuggling exploits inconsistencies in how front-end and back-end servers parse HTTP message boundaries.

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Affected Products (CPE)CVE.org

cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*
cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*
cpe:2.3:o:fortinet:fortios:7.6.0:*:*:*:*:*:*:*
CVE-2022-40684 CRITICAL POC
9.8 Oct 18

An authentication bypass using an alternate path or channel [CWE-288] in Fortinet FortiOS version 7.2.0 through 7.2.1 an

CVE-2025-64446 CRITICAL POC
9.8 Nov 14

Fortinet FortiWeb contains a relative path traversal allowing unauthenticated attackers to execute administrative comman

CVE-2024-55591 CRITICAL POC
9.8 Jan 14

FortiOS and FortiProxy contain an authentication bypass via the Node.js websocket module allowing unauthenticated remote

CVE-2024-21762 CRITICAL POC
9.8 Feb 09

A out-of-bounds write in Fortinet FortiOS versions 7.4.0 through 7.4.2, 7.2.0 through 7.2.6, 7.0.0 through 7.0.13, 6.4.0

CVE-2023-27997 CRITICAL
9.8 Jun 13

A heap-based buffer overflow vulnerability [CWE-122] in FortiOS version 7.2.4 and below, version 7.0.11 and below, versi

CVE-2025-58034 HIGH POC
7.2 Nov 18

Fortinet FortiWeb contains an authenticated OS command injection allowing privilege escalation to execute unauthorized c

CVE-2020-12812 CRITICAL
9.8 Jul 24

FortiOS SSL-VPN contains an improper authentication vulnerability that allows users to bypass two-factor authentication

CVE-2016-1909 CRITICAL POC
9.8 Jan 15

Fortinet FortiAnalyzer before 5.0.12 and 5.2.x before 5.2.5; FortiSwitch 3.3.x before 3.3.3; FortiCache 3.0.x before 3.0

CVE-2023-34992 CRITICAL POC
9.8 Oct 10

A improper neutralization of special elements used in an os command ('os command injection') vulnerability in Fortinet a

CVE-2016-6909 CRITICAL POC
9.8 Aug 24

Buffer overflow in the Cookie parser in Fortinet FortiOS 4.x before 4.1.11, 4.2.x before 4.2.13, and 4.3.x before 4.3.9

CVE-2026-104286 CRITICAL POC
9.8 Oct 01

Unauthenticated path traversal in Fortinet FortiMail (7.2.0-7.2.9, 7.4.0-7.4.8, 7.6.0-7.6.6 and 8.0.0-8.0.1) lets a remo

CVE-2026-39808 CRITICAL POC
9.8 Apr 14

OS command injection in Fortinet FortiSandbox 4.4.0-4.4.8 and FortiSandbox PaaS versions 21.3-23.4 enables remote unauth

Threat IntelligenceMISP

CISA Advisories
Sources: CISA (public domain)

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