CVE-2021-41030

Unauthenticated impersonation via replayed SAML messages

Published Dec 8, 2021 · Updated Oct 25, 2024

Authentication bypass in Fortinet FortiClient EMS 7.0.1 and earlier and 6.4.4 and earlier allows remote attackers to impersonate users. The SAML SSO flow accepts a previously valid authentication message again instead of rejecting its reuse. Exploitation requires interception of a valid SAML message and grants the impersonated user's EMS permissions without exposing an availability impact.

CVSS severity5.4
Medium
EPSS probability0.95%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Fortinet FortiClient EMS 7.0.1 and earlier and 6.4.4 and earlier allows remote attackers to impersonate users. The SAML SSO flow accepts a previously valid authentication message again instead of rejecting its reuse. Exploitation requires interception of a valid SAML message and grants the impersonated user's EMS permissions without exposing an availability impact.

The record

CVE
CVE-2021-41030
Published
Dec 8, 2021
Updated
Oct 25, 2024
Vendor
Fortinet
Product
FortiClient EMS
Classifications
CWE-294, T1550.001
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 8, 2021CVE 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=FortiClientEMS 7.0.1, 7.0.0, 6.4.4, 6.4.3, 6.4.2, 6.4.1, 6.4.0, 6.2.9, 6.2.8, 6.2.7, 6.2.6, 6.2.4, 6.2.3, 6.2.2, 6.2.1, 6.2.0

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Fortinet · FortiClient EMSversion=FortiClientEMS 7.0.1, 7.0.0, 6.4.4, 6.4.3, 6.4.2, 6.4.1, 6.4.0, 6.2.9, 6.2.8, 6.2.7, 6.2.6, 6.2.4, 6.2.3, 6.2.2, 6.2.1, 6.2.0

Published CVSS scores

5.4FortinetCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
6.4NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:N

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-294Authentication Bypass by Capture-replay
T1550.001Application Access Token

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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