VDB-436074 · CVE-2026-126258 · GCVE-0-2026-126258

Fortinet FortiOS 7.6.7/8.0.0 Proxy stack-based overflow

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 (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	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.
7.5	$0-$5k	0.00+

Summaryinfo

A vulnerability, which was classified as critical, was found in Fortinet FortiOS 7.6.7/8.0.0. Affected by this issue is some unknown functionality of the component Proxy. The manipulation results in stack-based overflow. This vulnerability is cataloged as CVE-2026-126258. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in Fortinet FortiOS 7.6.7/8.0.0. It has been classified as critical. Affected is some unknown functionality of the component Proxy. The manipulation with an unknown input leads to a stack-based overflow vulnerability. CWE is classifying the issue as CWE-121. The product writes past the end of a buffer that was allocated on the stack. This is going to have an impact on availability. CVE summarizes:

A stack-based buffer overflow vulnerability in Fortinet FortiOS 8.0.0, FortiOS 7.6.7 may allow an unauthenticated attacker with wad port access to crash proxy or ZTNA sessions via crafted HTTP or HTTPS requests.

The advisory is available at fortiguard.fortinet.com. This vulnerability is traded as CVE-2026-126258 since 11/10/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 11/11/2026).

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

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

Firewall Software

Vendor

Fortinet

Name

FortiOS

Version

License

commercial

Website

Vendor: https://www.fortinet.com/

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

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

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

Exploitinginfo

Class: Stack-based overflow
CWE: CWE-121 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

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

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

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-2026-126258 (🔒)

GCVE (CVE): GCVE-0-2026-126258
GCVE (VulDB): GCVE-100-436074

Entryinfo

Created: 11/11/2026 23:01
Changes: 11/11/2026 23:01 (63)
Complete: 🔍
Cache ID: 216::103