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CVE Record

CVE-2021-41019: An improper validation of certificate with host mismatch [CWE-297] vulnerability in FortiOS versions 6.4.6...

An improper validation of certificate with host mismatch [CWE-297] vulnerability in FortiOS versions 6.4.6 and below may allow the connection to a malicious LDAP server via options in GUI, leading to disclosure of sensitive information, such as AD credentials.

LowCVSS 3.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

This FortiOS issue can let a user be connected to a malicious LDAP server because certificate host matching is not properly validated. The main business concern is disclosure of sensitive information, including Active Directory credentials. Public data rates it low severity, with user interaction required and no KEV listing.

Executive priority

Handle through normal patch and configuration governance, with higher priority where FortiOS manages AD-backed authentication. The risk is credential disclosure, but available evidence indicates low severity and no confirmed active exploitation.

Technical view

CVE-2021-41019 is a CWE-297 certificate host mismatch validation flaw in FortiOS LDAP GUI options. A malicious LDAP server connection may result, exposing sensitive information such as AD credentials. The provided CVSS is 3.5, AV:A/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N.

Likely exposure

Likely exposure is Fortinet FortiOS versions 6.4.0 through 6.4.6 and 6.2.1 through 6.2.9, especially deployments using LDAP or AD authentication configuration.

Exploitation context

The source bundle does not show active exploitation, and CISA KEV is false. Exploitation requires user interaction and adjacent-network access per CVSS, limiting broad internet-scale risk. Evidence does not support claims of public exploit use.

Researcher notes

Evidence is limited to the CVE record and Fortinet advisory reference. The bundle names affected versions and impact but does not include detailed fixed-version text or exploit evidence. Avoid assuming products beyond FortiOS.

Mitigation direction

  • Review Fortinet advisory FG-IR-21-074 and apply vendor remediation guidance.
  • Inventory FortiOS versions and prioritize affected LDAP-enabled systems.
  • Verify LDAP server settings point only to trusted directory infrastructure.
  • Rotate AD credentials if logs suggest exposure to an untrusted LDAP server.

Validation and detection

  • Confirm FortiOS version against the affected 6.4.x and 6.2.x ranges.
  • Review LDAP configuration for unexpected hosts or certificate mismatches.
  • Check authentication logs for connections to unknown LDAP servers.
  • Document whether vendor advisory guidance has been applied.
Prepared
Confidence
high
Sources
3

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2021-41019 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Low
CVSS
3.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N/E:U/RL:U/RC:C

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
3.5CVSS 3.1LowCVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N/E:U/RL:U/RC:C2.11.4Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

3.5Low
CVSS 3.1 vector shape for CVE-2021-41019Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N/E:U/RL:U/RC:C

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
FortinetFortinet FortiOSFortiOS 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, 6.2.1Listed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.