Fortinet FortiAuthenticator up to 6.6.10/8.0.3 TCP infinite loop

CVSS Meta Temp Score
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CTI Interest Score
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7.5$0-$5k0.00+

Summaryinfo

A vulnerability was found in Fortinet FortiAuthenticator up to 6.6.10/8.0.3. It has been rated as critical. Affected by this issue is some unknown functionality of the component TCP Handler. Performing a manipulation results in infinite loop. This vulnerability is reported as CVE-2026-126237. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as critical, was found in Fortinet FortiAuthenticator up to 6.6.10/8.0.3. This affects an unknown function of the component TCP Handler. The manipulation with an unknown input leads to a infinite loop vulnerability. CWE is classifying the issue as CWE-835. The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. This is going to have an impact on availability. The summary by CVE is:

A loop with unreachable exit condition ('infinite loop') vulnerability in Fortinet FortiAuthenticator 8.0.0 through 8.0.3, FortiAuthenticator 6.6.0 through 6.6.10 may allow an attacker to cause a denial of service via crafted TCP requests.

It is possible to read the advisory at fortiguard.fortinet.com. This vulnerability is uniquely identified as CVE-2026-126237 since 11/10/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

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

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

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Version

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 7.5

VulDB Base Score: 7.5
VulDB Temp Score: 7.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (fortinet): 🔒

CVSSv2info

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

Exploitinginfo

Class: Infinite loop
CWE: CWE-835 / CWE-404
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

11/10/2026 CVE reserved
11/11/2026 +1 days Advisory disclosed
11/11/2026 +0 days VulDB entry created
11/11/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: fortinet.com

Advisory: fortiguard.fortinet.com
Status: Confirmed

CNA: fortinet
CVE: CVE-2026-126237 (🔒)

GCVE (CVE): GCVE-0-2026-126237
GCVE (VulDB): GCVE-100-436107

Entryinfo

Created: 11/11/2026 23:08
Changes: 11/11/2026 23:08 (61)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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