CVE-2018-13383

MEDIUM

6.5

CVSS Score

Published: May 29, 2019 at 05:20 PM UTC

Updated: June 17, 2026 at 01:39 AM UTC

2 products affected across 1 vendorFortiOSFortiProxy

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Severity

MEDIUM6.5

Exploitation

CISA KEV

Exploit prediction

EPSS 34%

SSVC

Active

Actively Exploited

CISA Known Exploited Vulnerabilities (KEV) Catalog

EPSS Score33.6%

EPSS (Exploit Prediction Scoring System) estimates a 33.6% chance this CVE is exploited in the wild within the next 30 days — higher than 98% of all CVEs. It complements CVSS: a high EPSS on a mid-severity CVE can still be urgent.

A heap buffer overflow in Fortinet FortiOS and FortiProxy may cause the SSL VPN web service termination for logged in users.

Required Action

Apply updates per vendor instructions.

Ransomware Use

Known

Added to KEV

Jan 10, 2022

Remediation Due

Jul 10, 2022

1570 days overdue

Notes

https://nvd.nist.gov/vuln/detail/CVE-2018-13383

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

FortiOS · Fortinet

95%

v ≤ 6.0.45.2.0 ≤ v < 5.2.155.4.0 ≤ v < 5.4.135.6.0 ≤ v < 5.6.116.0.0 ≤ v < 6.0.5

Affected range stops below 5.2.15, so it looks safe — our inference, not a vendor statement

Affected range stops below 5.4.13, so it looks safe — our inference, not a vendor statement

Affected range stops below 5.6.11, so it looks safe — our inference, not a vendor statement

Affected range stops below 6.0.5, so it looks safe — our inference, not a vendor statement

FortiProxy · Fortinet

95%

v ≤ 6.0.4v < 1.2.92.0.0

Affected range stops below 1.2.9, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (3)

x_refsource_CONFIRMMitigationVendor Advisory

Source: [email protected]

https://fortiguard.com/advisory/FG-IR-18-388

x_refsource_CONFIRMVendor Advisory

Source: [email protected]

https://fortiguard.com/advisory/FG-IR-20-229

US Government Resource

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-13383

SSVC — Action Prioritization

SSVCActiveNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUM[email protected]

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: REQUIRED
Scope: UNCHANGED
Confidentiality: NONE
Integrity: NONE
Availability: HIGH

Vector?

Quick Info

StatusANALYZED

CWE

CWE-787

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