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CVE Record

CVE-2021-26116: An improper neutralization of special elements used in an OS command vulnerability in the command line inte...

An improper neutralization of special elements used in an OS command vulnerability in the command line interpreter of FortiAuthenticator before 6.3.1 may allow an authenticated attacker to execute unauthorized commands via specifically crafted arguments to existing commands.

MediumCVSS 6.7Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

FortiAuthenticator versions before 6.3.1 contain a command injection weakness in the command line interpreter. An authenticated attacker could potentially run unauthorized operating system commands. The access requirements reduce broad internet risk, but compromise could affect confidentiality, integrity, and availability of an identity-related security appliance.

Executive priority

Prioritize remediation for internet-adjacent, identity-critical, or broadly administered FortiAuthenticator systems. The issue is not listed as actively exploited in the supplied sources, but successful abuse could materially affect a security authentication platform.

Technical view

CVE-2021-26116 is improper neutralization of special elements in FortiAuthenticator's CLI before 6.3.1. The CVSS vector is local, low complexity, high privileges, no user interaction, unchanged scope, with high CIA impact. The source says crafted arguments to existing commands may execute unauthorized commands.

Likely exposure

Exposure is limited to FortiAuthenticator deployments running versions before 6.3.1 where an attacker can authenticate and access the command line interpreter. Systems with tightly controlled administrator access have lower practical exposure.

Exploitation context

The bundle does not identify CISA KEV listing or active exploitation. CVSS temporal data marks exploit code maturity as functional, but no public exploit source is provided here. Treat exploitation status as unconfirmed beyond the CVSS signal.

Researcher notes

Key constraints are AV:L and PR:H, so validation should focus on authenticated CLI access paths, appliance versioning, and privilege boundaries. The public bundle does not provide exploit details, affected subcommands, execution context, or compensating controls beyond the fixed version boundary.

Mitigation direction

  • Upgrade FortiAuthenticator to 6.3.1 or later per the affected version boundary.
  • Review the Fortinet advisory for current vendor remediation guidance.
  • Restrict CLI and administrative access to trusted management networks and personnel.
  • Review privileged FortiAuthenticator accounts and remove unnecessary access.

Validation and detection

  • Inventory FortiAuthenticator versions and flag any instance before 6.3.1.
  • Confirm who has authenticated CLI or administrative access to affected appliances.
  • Check FortiAuthenticator and system logs for unusual CLI activity or unexpected changes.
  • Verify remediation against the Fortinet advisory after upgrade or compensating controls.
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-2021-26116 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
6.7 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:F/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
6.7CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:F/RL:U/RC:C0.85.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

6.7Medium
CVSS 3.1 vector shape for CVE-2021-26116Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:F/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 FortiAuthenticatorFortiAuthenticator before 6.3.1Listed
Weakness

CWE details

No CWE listed

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