Under non-default configuration, a stack-based buffer overflow in FortiOS version 6.0.10 and below, version 5…
- Severity
- High8.8CVSS 3.1, High
- Known exploited
- Not listed
- Exploit prediction
- 0.89%
- Published
- 19 Dec 2024Updated 17 Jun 2026 · Last verified 29 Sept 2026
Known remediation
Fixed releases per branch, as the vendor states them. Patcharo never infers a fix.
Fortinet FortiOS
Vendor advisory- 6.0Fixed after 6.0.10
- 5.6Fixed after 5.6.12
Workaround / Vendor remediation
Vendor remediation · FortiOS
Please upgrade to FortiOS versions 5.6.13 or above. Please upgrade to FortiOS versions 6.0.11 or above. FortiOS versions 6.2.0 and above are not impacted. FortiOS versions 6.4.0 and above are not impacted. Workaround: Please ensure that Fortiheartbeat and Endpoint-Compliance are not both enabled on the same interface. FortiHeartbeat and Endpoint-Compliance can be disabled on a particular interface by following the below CLI commands: config system interface edit interface set endpoint-compliance disable (<-- Disabled by default) set fortiheartbeat disable next end
Description
Title, description and vendor guidance are quoted from the source records.
Under non-default configuration, a stack-based buffer overflow in FortiOS version 6.0.10 and below, version 5.6.12 and below may allow a remote attacker authenticated to the SSL VPN to crash the FortiClient NAC daemon (fcnacd) and potentially execute arbitrary code via requesting a large FortiClient file name. We are not aware of proof of concept code successfully achieving the latter.
Weakness: CWE-121, CWE-787
Known exploited
Not listed in CISA KEV as of the last check.
Exploit prediction
0.89% probability of exploitation in the next 30 days (percentile 58%).
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
What the source states, per branch
Versions matched by Patcharo
Fortinet FortiOSSource: Fortinet (CVE record)
| Branch | Affected | Fixed in |
|---|---|---|
| 6.0 | 6.0.0 – 6.0.10 | Fixed after 6.0.10 |
| 5.6 | 5.6.0 – 5.6.12 | Fixed after 5.6.12 |
Versions not listed are stated unaffected by the vendor.
References
Provenance
Every fact on this page comes from the sources below. Nothing is written by an AI.
- Fortinet (CVE record)
- Fortinet (CVE record) · 29 Sept 2026 at 12:17 UTC · Parser patcharo-cve5/1.1.0
- NVD
- NVD · 27 Sept 2026 at 23:44 UTC · Parser patcharo-nvd/1.0.0
- FIRST EPSS
- FIRST EPSS · 30 Sept 2026 at 00:17 UTC · Parser patcharo-epss/1.0.0
Last verified: 29 Sept 2026 at 12:17 UTC