CVE-2018-13383

Exp

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: 2019-05-29 Last update: 2025-10-24 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-13383 is rated Critical Active Threat (81.6/100): CVSS Medium severity, with high exploitation likelihood (EPSS 33.65%, 98th percentile). CISA KEV confirms active exploitation (added 2022-01-10) affecting Fortinet / FortiOS and FortiProxy. a weakness (CWE-787) Unauthenticated remote administrative access may be possible. EPSS rose +31.89% over the last day, indicating growing attacker interest. The CISA remediation deadline has passed—treat as an emergency patch priority.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

CISA KEV Record for CVE-2018-13383

Name: Fortinet FortiOS and FortiProxy Out-of-bounds Write · CISA KEV detail

Exploit added: 2022-01-10

Action due: 2022-07-10

Required action: Apply updates per vendor instructions.

Exploit prediction scoring system (EPSS) score for CVE-2018-13383

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 1.76% 33.65% +31.89%
2 2026-05-02 1.14% 1.76% +0.62%
3 2026-04-29 — 1.14% —

Full EPSS history (19 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-13383

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.8 1.4 [email protected]
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2018-13383

Affected software / configurations for CVE-2018-13383

Vendor Product Version Raw CPE
fortinet fortiproxy < 1.2.9 cpe:2.3:a:fortinet:fortiproxy:*:*:*:*:*:*:*:*
fortinet fortiproxy 2.0.0 cpe:2.3:a:fortinet:fortiproxy:2.0.0:*:*:*:*:*:*:*
fortinet fortios >= 5.2.0, < 5.2.15 cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*
fortinet fortios >= 5.4.0, < 5.4.13 cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*
fortinet fortios >= 5.6.0, < 5.6.11 cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*
fortinet fortios >= 6.0.0, < 6.0.5 cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*

References for CVE-2018-13383

cvelogic Threat Intelligence