Security Resilience

CVE-2018-13383

Memory Safety in Fortinet Fortios 5.2.0 – 5.2.15

CISA KEVActive ExploitationEUVD ExploitedRansomware-linkedMemory Safety
Published
29 May 2019
Modified
24 October 2025
KEV Added
10 January 2022
Patch / advisory
View advisory
CVSS Score v3.1 4.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
EPSS Score 0.34 98th percentile
Risk Priority 75 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2018-13383 is a medium-severity Out-of-bounds Write (CWE-787) vulnerability in Fortinet Fortios. Its CVSS base score is 4.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Security Account Manager (T1003.002); ranked in the top 2% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

The vulnerability is a heap buffer overflow, tracked as CWE-787, affecting the SSL VPN web portal component in Fortinet FortiOS versions 6.0.0 through 6.0.4, 5.6.0 through 5.6.10, 5.4.0 through 5.4.12, and 5.2.14 and earlier, as well as FortiProxy versions 2.0.0, 1.2.8 and earlier. It arises from a failure to properly handle javascript href data when proxying webpages and is rated 4.3 on CVSS 3.1 with impacts limited to availability.

An authenticated attacker with network access can trigger the flaw to cause termination of the SSL VPN web service for logged-in users, producing a denial-of-service condition without user interaction required.

The issue appears in FortiGuard advisories FG-IR-18-388 and FG-IR-20-229, and it is catalogued by CISA among vulnerabilities observed in active exploitation.

EU & UK References

Vulnerability Data

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…

more

logged in users due to a failure to properly handle javascript href data when proxying webpages.

CWE(s)
CWE-787
KEV Date Added
10 January 2022

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003.002 Security Account Manager Credential Access
Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored.
attack.mitre.org →
T1003.004 LSA Secrets Credential Access
Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts.
attack.mitre.org →
T1003.008 /etc/passwd and /etc/shadow Credential Access
Adversaries may attempt to dump the contents of <code>/etc/passwd</code> and <code>/etc/shadow</code> to enable offline password cracking.
attack.mitre.org →
T1006 Direct Volume Access Stealth
Adversaries may directly access a volume to bypass file access controls and file system monitoring.
attack.mitre.org →
T1007 System Service Discovery Discovery
Adversaries may try to gather information about registered local system services.
attack.mitre.org →
T1012 Query Registry Discovery
Adversaries may interact with the Windows Registry to gather information about the system, configuration, and installed software.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-21762Same product: Fortinet Fortiosboth on KEV
CVE-2023-42789Same product: Fortinet Fortios
CVE-2023-22640Same product: Fortinet Fortios
CVE-2023-22639Same product: Fortinet Fortios
CVE-2023-33308Same product: Fortinet Fortios
CVE-2023-27997Same product: Fortinet Fortiosboth on KEV
CVE-2024-52963Same product: Fortinet Fortios
CVE-2022-42475Same product: Fortinet Fortiosboth on KEV
CVE-2024-23110Same product: Fortinet Fortios
CVE-2023-29182Same product: Fortinet Fortios

Affected Assets

fortinet
fortiproxy
2.0.0 · ≤ 1.2.9
fortinet
fortios
5.2.0 — 5.2.15 · 5.4.0 — 5.4.13 · 5.6.0 — 5.6.11

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SI-16 Memory Protection
addresses: CWE-787

Out-of-bounds writes that corrupt control flow or inject shellcode are rendered non-executable by the same memory protections.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

ID.RA-01 partial match
blocks

Vulnerability scanning and recording can discover out-of-bounds write flaws so they can be remediated.

PR.PS-02 partial match
blocks

Patching or replacing vulnerable software directly eliminates known instances of this coding weakness.

PR.PS-06 partial match
blocks

Secure-development practices (static analysis, bounds checking, code review) are the primary means of preventing out-of-bounds writes.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.7.2 Physical entry partial match
removes

References