CVE-2021-41019

Credential disclosure via LDAP hostname validation failure

Published Nov 2, 2021 · Updated Oct 25, 2024

Improper certificate validation in Fortinet FortiOS 6.2.1 through 6.2.9 and 6.4.0 through 6.4.6 allows attackers to obtain AD credentials. FortiOS accepts an LDAP server certificate whose host name does not match the configured server, allowing a GUI-initiated connection to an attacker-controlled endpoint. Exploitation requires user interaction and adjacent-network access; the reported consequence is limited to disclosure of sensitive LDAP data, including AD credentials.

CVSS severity3.5
Low
EPSS probability0.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper certificate validation in Fortinet FortiOS 6.2.1 through 6.2.9 and 6.4.0 through 6.4.6 allows attackers to obtain AD credentials. FortiOS accepts an LDAP server certificate whose host name does not match the configured server, allowing a GUI-initiated connection to an attacker-controlled endpoint. Exploitation requires user interaction and adjacent-network access; the reported consequence is limited to disclosure of sensitive LDAP data, including AD credentials.

The record

CVE
CVE-2021-41019
Published
Nov 2, 2021
Updated
Oct 25, 2024
Vendor
Fortinet
Product
FortiOS
Classifications
CWE-297, CWE-295, T1557
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 2, 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=FortiOS 6.4.6, 6.4.5, 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, 6.2.5, 6.2.4, 6.2.3, 6.2.2, 6.2.1

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Fortinet · FortiOSversion=FortiOS 6.4.6, 6.4.5, 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, 6.2.5, 6.2.4, 6.2.3, 6.2.2, 6.2.1

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
3.2FortinetCVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N/E:U/RL:U/RC:C
3.5FortinetCVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
4.3NIST NVDAV:N/AC:M/Au:N/C:P/I:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-297Improper Validation of Certificate with Host Mismatch
CWE-295Improper Certificate Validation
T1557Adversary-in-the-Middle

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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