CVE-2018-13383
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…
- 4.3MediumCVSS base score
- 30.7%Exploitation in 30 daysEPSS · top 1.7% of all CVEs
- YesKnown exploitedin CISA's KEV since 10 Jan 2022
- YesPublic exploitsa reference or SSVC says so
Description
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.
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as Fortinet FortiOS and FortiProxy Out-of-bounds Write.
- Added
- 10 Jan 2022
- Fix due (US federal)
- 10 Jul 2022
- Used by ransomware
- Known
Apply updates per vendor instructions.
ENISA's EU Vulnerability Database lists it as exploited, from CISA's KEV, since 10 Jan 2022.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: it is being exploited.
Timeline
ID reserved
By fortinet
- 11 months later
· 11 months later
Published
- 3 years later
· 3 years later
Added to CISA KEV
Known exploited, also by ransomware
- 4 years later
· 4 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| fortinetCNA (assigner) | 3.1 | Medium4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L |
| NVDNVD · Analyzed | 3.1 | Medium6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 30.7% · top 1.7% of all CVEs (10 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.3.
Affected products
Fortinet · Fortinet FortiOS and FortiProxy
- affected 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, FortiProxy 2.0.0, 1.2.8 and earlier
References
3
- https://fortiguard.com/advisory/FG-IR-18-388 (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://fortiguard.com/advisory/FG-IR-20-229 (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-13383 (opens in a new tab)government-resource
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2018-5327 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2018-13383)Record last updated .