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CVE Record

CVE-2021-22131: A improper validation of certificate with host mismatch in Fortinet FortiTokenAndroid version 5.0.3 and bel...

A improper validation of certificate with host mismatch in Fortinet FortiTokenAndroid version 5.0.3 and below, Fortinet FortiTokeniOS version 5.2.0 and below, Fortinet FortiTokenWinApp version 4.0.3 and below allows attacker to retrieve information disclosed via man-in-the-middle attacks.

MediumCVSS 6.4Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-22131 affects Fortinet FortiToken apps that may not properly reject a certificate when the hostname does not match. In practical terms, a user on a hostile or intercepted network could be exposed to information disclosure through a man-in-the-middle condition.

Executive priority

Treat as a moderate priority hygiene issue for MFA clients. It is not reported as actively exploited here, but affected authentication users on hostile networks could face sensitive information exposure.

Technical view

FortiTokenAndroid 5.0.3 and below, FortiTokeniOS 5.2.0 and below, and FortiTokenWinApp 4.0.3 and below are listed as affected. The CVSS 3.1 score is 6.4 with adjacent-network attack vector, high complexity, no privileges, required user interaction, and high confidentiality and availability impact.

Likely exposure

Exposure is most likely where organizations still allow affected FortiToken mobile or Windows app versions. Risk is higher for users operating on untrusted local networks or networks where traffic interception is plausible.

Exploitation context

The provided sources do not show CISA KEV listing or confirmed active exploitation. The CVSS vector includes proof-of-concept exploit maturity, but the bundle does not provide operational exploit details.

Researcher notes

The advisory data identifies host mismatch certificate validation failure across Android, iOS, and Windows FortiToken clients. No CWE is provided in the bundle. Validation should focus on version inventory and vendor-advisory alignment, not exploit reproduction.

Mitigation direction

  • Review Fortinet advisory FG-IR-21-024 for vendor remediation guidance.
  • Inventory FortiTokenAndroid, FortiTokeniOS, and FortiTokenWinApp versions in use.
  • Prioritize replacement or update of versions listed as affected.
  • Warn affected users to avoid untrusted networks until remediation is confirmed.

Validation and detection

  • Compare deployed FortiToken app versions against the affected version list.
  • Check mobile device management and endpoint inventory for FortiToken installations.
  • Confirm remediation guidance directly against Fortinet’s advisory.
  • Record whether any affected versions remain in privileged or remote-access user groups.
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

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

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CVE-2021-22131 mapping review

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

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
6.4 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:H/E:P/RL:X/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
6.4CVSS 3.1MediumCVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:H/E:P/RL:X/RC:C1.25.2Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

6.4Medium
CVSS 3.1 vector shape for CVE-2021-22131Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:H/E:P/RL:X/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 FortiTokenAndroid, Fortinet FortiTokeniOS, Fortinet FortiTokenWinAppFortiTokenAndroid 5.0.3, 5.0.2, 4.5.0, 4.4.0, 4.3.0, 4.2.2, 4.2.1, 4.1.1, 4.0.1, 4.0.0, 3.0.4, 3.0.3, 3.0.2, 3.0.1, 3.0.0, 0.4.20, 0.4.10, FortiTokeniOS 5.2.0, 4.3.0, 4.2.0, 4.1.1, 3.0.5, 3.0.4, 3.0.3, 3.0.2, 3.0.1, FortiTokenWinApp 4.0.3, 3.0.1, 3.0.0Listed
Weakness

CWE details

No CWE listed

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