How severe is CVE-2021-41028?

CVE-2021-41028 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over an adjacent network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability high.

Is CVE-2021-41028 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-41028?

CVE-2021-41028 primarily affects Fortinet Forticlient. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-41028?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-41028 published?

CVE-2021-41028 was published on 2021-12-16 and last updated on 2026-06-17.

CVE-2021-41028

CVE-2021-41028 is a high-severity vulnerability in Fortinet Forticlient with a CVSS 3.x base score of 8.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-295.

Key facts

Severity: High (CVSS 3.x base score 8.2)
CVSS v2: 5.4
EPSS exploit prediction: 0% (12th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-295
Affected product: Fortinet Forticlient
Published: 2021-12-16
Last modified: 2026-06-17

Description

A combination of a use of hard-coded cryptographic key vulnerability [CWE-321] in FortiClientEMS 7.0.1 and below, 6.4.6 and below and an improper certificate validation vulnerability [CWE-297] in FortiClientWindows, FortiClientLinux and FortiClientMac 7.0.1 and below, 6.4.6 and below may allow an unauthenticated and network adjacent attacker to perform a man-in-the-middle attack between the EMS and the FCT via the telemetry protocol.

Frequently asked questions

What is CVE-2021-41028?: A combination of a use of hard-coded cryptographic key vulnerability [CWE-321] in FortiClientEMS 7.0.1 and below, 6.4.6 and below and an improper certificate validation vulnerability [CWE-297] in FortiClientWindows, FortiClientLinux and FortiClientMac 7.0.1 and below, 6.4.6 and below may allow an unauthenticated and network adjacent attacker to perform a man-in-the-middle attack between the EMS and the FCT via the telemetry protocol.
How severe is CVE-2021-41028?: CVE-2021-41028 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over an adjacent network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability high.
Is CVE-2021-41028 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-41028?: CVE-2021-41028 primarily affects Fortinet Forticlient. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-41028?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-41028 published?: CVE-2021-41028 was published on 2021-12-16 and last updated on 2026-06-17.

References

https://fortiguard.com/advisory/FG-IR-21-075

Affected products (12)

cpe:2.3:a:fortinet:forticlient:*:*:*:*:*:macos:*:*
cpe:2.3:a:fortinet:forticlient:*:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:*:*:*:*:*:linux:*:*
cpe:2.3:a:fortinet:forticlient:7.0.0:*:*:*:*:linux:*:*
cpe:2.3:a:fortinet:forticlient:7.0.0:*:*:*:*:macos:*:*
cpe:2.3:a:fortinet:forticlient:7.0.0:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient:7.0.1:*:*:*:*:linux:*:*
cpe:2.3:a:fortinet:forticlient:7.0.1:*:*:*:*:macos:*:*
cpe:2.3:a:fortinet:forticlient:7.0.1:*:*:*:*:windows:*:*
cpe:2.3:a:fortinet:forticlient_endpoint_management_server:*:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:forticlient_endpoint_management_server:7.0.0:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:forticlient_endpoint_management_server:7.0.1:*:*:*:*:*:*:*

More vulnerabilities in Fortinet Forticlient

CVE-2019-17658 — Critical (CVSS 9.8): An unquoted service path vulnerability in the FortiClient FortiTray component of FortiClientWindows v6.2.2 and prior…
CVE-2023-45590 — Critical (CVSS 9.6): An improper control of generation of code ('code injection') in Fortinet FortiClientLinux version 7.2.0, 7.0.6 through…
CVE-2020-15934 — High (CVSS 8.8): An execution with unnecessary privileges vulnerability in the VCM engine of FortiClient for Linux versions 6.2.7 and…
CVE-2017-14184 — High (CVSS 8.8): An Information Disclosure vulnerability in Fortinet FortiClient for Windows 5.6.0 and below versions, FortiClient for…
CVE-2016-8493 — High (CVSS 8.8): In FortiClientWindows 5.4.1 and 5.4.2, an attacker may escalate privilege via a FortiClientNamedPipe vulnerability.
CVE-2021-43066 — High (CVSS 8.4): A external control of file name or path in Fortinet FortiClientWindows version 7.0.2 and below, version 6.4.6 and…

All CVEs affecting Fortinet Forticlient →

Other CWE-295 (Improper Certificate Validation) vulnerabilities

CVE-2026-4370 — Critical (CVSS 10.0): A vulnerability was identified in Juju from version 3.2.0 until 3.6.19 and from version 4.0 until 4.0.4, where the…
CVE-2026-30836 — Critical (CVSS 10.0): Step CA is an online certificate authority for secure, automated certificate management for DevOps. Versions 0.30.0-rc6…
CVE-2025-68121 — Critical (CVSS 10.0): During session resumption in crypto/tls, if the underlying Config has its ClientCAs or RootCAs fields mutated between…
CVE-2022-20703 — Critical (CVSS 10.0): Multiple vulnerabilities in Cisco Small Business RV160, RV260, RV340, and RV345 Series Routers could allow an attacker…
CVE-2021-1471 — Critical (CVSS 9.9): Multiple vulnerabilities in Cisco Jabber for Windows, Cisco Jabber for MacOS, and Cisco Jabber for mobile platforms…
CVE-2026-20184 — Critical (CVSS 9.8): A vulnerability in the integration of single sign-on (SSO) with Control Hub in Cisco Webex Services could have allowed…

Browse all CWE-295 (Improper Certificate Validation) vulnerabilities →