Fortinet FortiOS up to 7.6.6 improper authentication

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
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CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.9$0-$5k0.00+

Summaryinfo

A vulnerability identified as very critical has been detected in Fortinet FortiOS up to 7.6.6. Impacted is an unknown function. The manipulation leads to improper authentication. This vulnerability is documented as CVE-2026-121530. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Fortinet FortiOS up to 7.6.6. It has been rated as very critical. This issue affects some unknown functionality. The manipulation with an unknown input leads to a improper authentication vulnerability. Using CWE to declare the problem leads to CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

A improper authentication vulnerability in Fortinet FortiOS 7.6.0 through 7.6.6 may allow a remote authenticated attacker to gain improper access control via an invalid token after entering a valid username and password

The advisory is shared at fortiguard.fortinet.com. The identification of this vulnerability is CVE-2026-121530 since 11/03/2026. The exploitation is known to be easy. The attack may be initiated remotely. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 11/10/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.9
VulDB Meta Temp Score: 7.9

VulDB Base Score: 9.1
VulDB Temp Score: 9.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 6.6
CNA Vector (fortinet): 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Improper authentication
CWE: CWE-287
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

11/03/2026 CVE reserved
11/10/2026 +7 days Advisory disclosed
11/10/2026 +0 days VulDB entry created
11/10/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: fortinet.com

Advisory: fortiguard.fortinet.com
Status: Confirmed

CNA: fortinet
CVE: CVE-2026-121530 (🔒)

GCVE (CVE): GCVE-0-2026-121530
GCVE (VulDB): GCVE-100-434681

Entryinfo

Created: 11/10/2026 21:52
Changes: 11/10/2026 21:52 (62)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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