FortiOS
CVE-2018-13383: FortiOS and FortiProxy Out-of-bounds Write
A heap buffer overflow in Fortinet FortiOS 6.0.0 through 6.0.4, 5.6.0 through 5.6.10, 5.4.0 through 5.4.12, 5.2.14 and earlier and FortiProxy 2.0.0, 1.2.8 and earlier in the SSL VPN web portal may cause the SSL VPN web service termination for logged in users due to a failure to properly handle javascript href data when proxying webpages.
Published
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| Fortinet FortiOS and FortiProxy FortiOS 6.0 | See the advisory |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
A heap buffer overflow in Fortinet FortiOS 6.0.0 through 6.0.4, 5.6.0 through 5.6.10, 5.4.0 through 5.4.12, 5.2.14 and earlier and FortiProxy 2.0.0, 1.2.8 and earlier in the SSL VPN web portal may cause the SSL VPN web service termination for logged in users due to a failure to properly handle javascript href data when proxying webpages.
Exploitation
CISA lists this CVE as exploited in the wild since 10 Jan 2022, including in ransomware campaigns.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 10 Oct 2026.