CVE-2018-13379Known exploitationPublic exploitNetwork attack vector

Unauthenticated file disclosure via language-file path traversal

Published Jun 4, 2019 · Updated Oct 21, 2025

Path traversal in Fortinet FortiOS and FortiProxy SSL VPN portals allows remote attackers to read system files via crafted HTTP requests. The FortiOS language-file handler inserts the untrusted lang parameter into a pathname without traversal checks, and snprintf truncation removes the appended .json restriction. Exploitation requires a reachable SSL VPN portal but no authentication, and exposed session files contain plaintext VPN credentials; code execution requires a separate vulnerability.

CVSS severity9.1
Critical
EPSS probability100.00%
Next 30 days · Nov 1, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Fortinet FortiOS and FortiProxy SSL VPN portals allows remote attackers to read system files via crafted HTTP requests. The FortiOS language-file handler inserts the untrusted lang parameter into a pathname without traversal checks, and snprintf truncation removes the appended .json restriction. Exploitation requires a reachable SSL VPN portal but no authentication, and exposed session files contain plaintext VPN credentials; code execution requires a separate vulnerability.

The record

CVE
CVE-2018-13379
Published
Jun 4, 2019
Updated
Oct 21, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-22, T1190, T1552.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 4, 2019CVE publishedPublication date reported by the CVE source.
  2. Oct 21, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.1FortinetCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsShadowserver observations through Sep 28, 2026. Gaps indicate unavailable data.
Sep 22, 2026Sep 28, 2026
View daily counts
Reporting dayUnique IPs
Sep 22, 202627
Sep 23, 202613
Sep 24, 202611
Sep 25, 202653
Sep 26, 202679
Sep 27, 202672
Sep 28, 202671
Latest reporting daySep 28, 2026
Latest daily unique IPs71
Prior 30-day average61.6
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1190Exploit Public-Facing Application
T1552.001Credentials In Files

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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