CVE-2020-9291

Local privilege escalation via symlinked temp files

Published Jun 1, 2020 · Updated Oct 25, 2024

Insecure temporary file handling in FortiClient for Windows 6.2.1 and earlier allows local users to gain elevated privileges via a symlink attack. The client exhausts predictable temporary-file names, then follows an attacker-created symbolic link when creating a privileged file. A local user account is required, and successful exploitation can compromise confidentiality, integrity, and availability through elevated privileges.

CVSS severity7.8
High
EPSS probability0.53%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insecure temporary file handling in FortiClient for Windows 6.2.1 and earlier allows local users to gain elevated privileges via a symlink attack. The client exhausts predictable temporary-file names, then follows an attacker-created symbolic link when creating a privileged file. A local user account is required, and successful exploitation can compromise confidentiality, integrity, and availability through elevated privileges.

The record

CVE
CVE-2020-9291
Published
Jun 1, 2020
Updated
Oct 25, 2024
Vendor
Fortinet
Product
FortiClient for Windows
Classifications
CWE-668, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 1, 2020CVE publishedPublication date reported by the CVE source.
  2. Oct 25, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=FortiClient for Windows 6.2.1 and earlier and FortiClient for Windows 6.0.9 and earlier

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Fortinet · FortiClient for Windowsversion=FortiClient for Windows 6.2.1 and earlier and FortiClient for Windows 6.0.9 and earlier

Published CVSS scores

4.6NVDAV:L/AC:L/Au:N/C:P/I:P/A:P
7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.3FortinetCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-668Exposure of Resource to Wrong Sphere
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

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Your stack

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