How severe is CVE-2018-13383?

CVE-2018-13383 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2018-13383 being actively exploited?

Yes. CVE-2018-13383 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-01-10, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2018-13383?

CVE-2018-13383 primarily affects Fortinet Fortiproxy. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-13383?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2018-13383 have an EU (EUVD) identifier?

Yes. CVE-2018-13383 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2018-5327. It is also flagged as exploited in the EUVD (since 2022-01-10).

When was CVE-2018-13383 published?

CVE-2018-13383 was published on 2019-05-29 and last updated on 2026-06-17.

CVE-2018-13383

CVE-2018-13383 is a medium-severity vulnerability in Fortinet Fortiproxy with a CVSS 3.x base score of 4.3. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2022-01-10). The underlying weakness is classified as CWE-787.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.3
EPSS exploit prediction: 34% (98th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2022-01-10)
EU (EUVD) id: EUVD-2018-5327
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2022-01-10)
Weakness: CWE-787
Affected product: Fortinet Fortiproxy
Published: 2019-05-29
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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 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.
How severe is CVE-2018-13383?: CVE-2018-13383 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2018-13383 being actively exploited?: Yes. CVE-2018-13383 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-01-10, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2018-13383?: CVE-2018-13383 primarily affects Fortinet Fortiproxy. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-13383?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2018-13383 have an EU (EUVD) identifier?: Yes. CVE-2018-13383 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2018-5327. It is also flagged as exploited in the EUVD (since 2022-01-10).
When was CVE-2018-13383 published?: CVE-2018-13383 was published on 2019-05-29 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:fortinet:fortiproxy:*:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:fortiproxy:2.0.0:*:*:*:*:*:*:*
cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*

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