A heap-based buffer overflow vulnerability in the processing of Link Control Protocol messages in FortiGate v…
- Severity
- High7.5CVSS 3.1, High
- Known exploited
- Not listed
- Exploit prediction
- 0.79%
- 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- 6.4Fixed after 6.4.1
- 6.2Fixed after 6.2.4
- 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. Please upgrade to FortiOS versions 6.2.5 or above. Please upgrade to FortiOS versions 6.4.2 or above. Workaround: Disable tunnel mode.
Description
Title, description and vendor guidance are quoted from the source records.
A heap-based buffer overflow vulnerability in the processing of Link Control Protocol messages in FortiGate versions 5.6.12, 6.0.10, 6.2.4 and 6.4.1 and earlier may allow a remote attacker with valid SSL VPN credentials to crash the SSL VPN daemon by sending a large LCP packet, when tunnel mode is enabled. Arbitrary code execution may be theoretically possible, albeit practically very difficult to achieve in this context
Weakness: CWE-122, CWE-787
Known exploited
Not listed in CISA KEV as of the last check.
Exploit prediction
0.79% probability of exploitation in the next 30 days (percentile 55%).
CVSS:3.1/AV:N/AC:H/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 |
|---|---|---|
| 6.4 | 6.4.0 – 6.4.1 | Fixed after 6.4.1 |
| 6.2 | 6.2.0 – 6.2.4 | Fixed after 6.2.4 |
| 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