CVE-2016-6909Fortios Memory Corruption
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 and FortiSwitch before 3.4.3 allows remote attackers to execute arbitrary code via a crafted HTTP request, aka EGREGIOUSBLUNDER.
Published Aug 24, 2016 · Updated May 6, 2026
Key Facts
Patch immediately- CVE-2016-6909 is a critical-severity vulnerability (CVSS 9.8 v3) affecting Fortios (Fortinet), Fortiswitch (Fortinet).
- It is exploited in the wild, listed in Industry KEV feed since Sep 28, 2016. Public exploit code is available.
- EPSS estimates a 50% probability of exploitation in the next 30 days.
- Fixed versions are available, including Fortios 4.1.11, Fortiswitch 3.4.2.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Scores
CVSS v3
9.8
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
50%
Higher than 98.8% of all scored CVEs
Exploit maturity
Proof of concept
ATLAS score
71/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Sep 28, 2016
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Proof of concept
Public exploit code
3
Proof-of-concept links
In-the-wild evidence
3
Reports of active use
Advisories And Exploit References
Description
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 and FortiSwitch before 3.4.3 allows remote attackers to execute arbitrary code via a crafted HTTP request, aka EGREGIOUSBLUNDER.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Sep 28, 2016 | n/a | Not reported |
Affected Products
2 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| FortiosFortinet | See advisory | 4.1.11 |
| FortiswitchFortinet | See advisory | 3.4.2 |
Patched Releases
Fortios
4.1.11
Fortiswitch
3.4.2
Timeline
Publicly disclosed
Aug 24, 2016
Added to Industry KEV feed
Sep 28, 2016
Last updated
May 6, 2026
Weakness Type
- CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
References
- advisoryfortiguard.com · FG-IR-16-023
- advisorymusalbas.com · equation-group-firewall-operations-catalogue.ht…
- advisory92523
- advisory1036643
- exploitpacketstormsecurity.com · EGREGIOUSBLUNDER-Fortigate-Remote-Code-Executio…
FAQ
Common Questions.
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 and FortiSwitch before 3.4.3 allows remote attackers to execute arbitrary code via a crafted HTTP request, aka EGREGIOUSBLUNDER.
Affected: Fortios (Fortinet); Fortiswitch (Fortinet). The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed since Sep 28, 2016.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including Fortios 4.1.11, Fortiswitch 3.4.2.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Is CVE-2016-6909 On Your Attack Surface?
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