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CVE Record

CVE-2021-43076: An improper privilege management vulnerability [CWE-269] in FortiADC versions 6.2.1 and below, 6.1.5 and be...

An improper privilege management vulnerability [CWE-269] in FortiADC versions 6.2.1 and below, 6.1.5 and below, 6.0.4 and below, 5.4.5 and below and 5.3.7 and below may allow a remote authenticated attacker with restricted user profile to modify the system files using the shell access.

MediumCVSS 6.3Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

A logged-in FortiADC user with limited rights may be able to change system files through shell access. This is not described as unauthenticated compromise, but it weakens role separation and could turn a restricted account into a broader appliance integrity risk.

Executive priority

Treat this as a moderate operational risk. It is most urgent where FortiADC management access is broadly reachable, shared accounts exist, or restricted users are delegated shell access. Prioritize remediation during normal network appliance maintenance windows unless local exposure is high.

Technical view

CVE-2021-43076 is CWE-269 improper privilege management in FortiADC. A remote authenticated attacker with a restricted user profile may modify system files using shell access. The CVSS 3.1 score is 6.3 with low attack complexity, required low privileges, no user interaction, and limited confidentiality, integrity, and availability impact.

Likely exposure

Exposure is limited to Fortinet FortiADC versions 6.2.1 and below, 6.1.5 and below, 6.0.4 and below, 5.4.5 and below, and 5.3.7 and below. Systems without shell access for restricted users may have lower practical exposure, but the source bundle does not define compensating controls.

Exploitation context

The source bundle does not cite active exploitation, and the CVE is not marked as CISA KEV. Exploitation requires valid authentication with a restricted profile, which makes credential hygiene and management-plane access controls important.

Researcher notes

The provided evidence identifies affected FortiADC branches and the privilege-management failure, but does not include exploit details, proof of concept, or explicit fixed versions. Avoid assuming unauthenticated access or confirmed exploitation without additional vendor or KEV evidence.

Mitigation direction

  • Review Fortinet PSIRT FG-IR-21-215 for the vendor-approved remediation path.
  • Upgrade affected FortiADC systems according to Fortinet guidance.
  • Restrict management and shell access to trusted administrators only.
  • Review restricted user accounts and remove unnecessary access.
  • Monitor FortiADC system file changes and administrative activity.

Validation and detection

  • Inventory all FortiADC appliances and record exact firmware versions.
  • Confirm whether any listed affected versions remain deployed.
  • Review accounts with restricted profiles and shell access.
  • Check logs for unexpected system file modifications.
  • Verify Fortinet PSIRT remediation 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-2021-43076 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
6.3 (3.1)
Known Exploited
No
Published

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

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
6.3CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:F/RL:X/RC:X2.83.4Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

6.3Medium
CVSS 3.1 vector shape for CVE-2021-43076Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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
FortinetFortiADCFortiADC 6.2.1, 6.2.0, 6.1.5, 6.1.4, 6.1.3, 6.1.2, 6.1.1, 6.1.0, 6.0.4, 6.0.3, 6.0.2, 6.0.1, 6.0.0, 5.4.5, 5.4.4, 5.4.3, 5.4.2, 5.4.1, 5.4.0, 5.3.7, 5.3.6, 5.3.5, 5.3.4, 5.3.3, 5.3.2, 5.3.1, 5.3.0Listed
Weakness

CWE details

No CWE listed

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