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CVE Record

CVE-2021-43071: A heap-based buffer overflow in Fortinet FortiWeb version 6.4.1 and 6.4.0, version 6.3.15 and below, versio...

A heap-based buffer overflow in Fortinet FortiWeb version 6.4.1 and 6.4.0, version 6.3.15 and below, version 6.2.6 and below allows attacker to execute unauthorized code or commands via crafted HTTP requests to the LogReport API controller.

HighCVSS 8.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2021-43071 is a high-severity Fortinet FortiWeb flaw. An authenticated attacker could send crafted HTTP requests to the LogReport API controller and potentially run unauthorized code or commands on the appliance.

Executive priority

Treat this as a priority remediation item for affected FortiWeb deployments because compromise could affect confidentiality, integrity, and availability. Urgency is highest for reachable appliances with many authenticated users or weak account controls.

Technical view

The issue is a heap-based buffer overflow in FortiWeb 6.4.1/6.4.0, 6.3.15 and below, and 6.2.6 and below. The CVSS 3.1 vector is network-reachable, low complexity, low privileges, no user interaction, with high confidentiality, integrity, and availability impact.

Likely exposure

Exposure is most relevant where affected FortiWeb versions are deployed and the LogReport API controller is reachable by authenticated users. The source bundle does not identify affected CPEs, internet exposure prevalence, or default accessibility.

Exploitation context

The source bundle does not show CISA KEV listing or confirmed active exploitation. The CVSS vector includes E:P, indicating proof-of-concept exploit maturity, but no cited source here confirms exploitation in the wild.

Researcher notes

Evidence supports authenticated network exploitation against the LogReport API controller through a heap overflow. The bundle does not provide CWE mapping, exploit details, fixed versions, indicators of compromise, or active exploitation evidence.

Mitigation direction

  • Identify FortiWeb appliances and compare versions against the affected version list.
  • Review Fortinet advisory FG-IR-21-188 for fixed releases and vendor-approved mitigations.
  • Prioritize upgrade or mitigation where affected FortiWeb interfaces are reachable by users.
  • Restrict access to FortiWeb administrative and API surfaces where operationally feasible.
  • Monitor FortiWeb logs for unusual LogReport API activity.

Validation and detection

  • Confirm FortiWeb version numbers from appliance inventory or management records.
  • Verify whether 6.4.1, 6.4.0, 6.3.15 or below, or 6.2.6 or below are present.
  • Check which users or networks can reach the LogReport API controller.
  • Review logs for unexpected authenticated HTTP requests involving LogReport functionality.
  • Confirm remediation status against Fortinet advisory FG-IR-21-188.
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-2021-43071 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
High
CVSS
8.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/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
8.8CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:C2.85.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

8.8High
CVSS 3.1 vector shape for CVE-2021-43071Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 FortiWebFortiWeb 6.4.1, 6.4.0, 6.3.16, 6.3.15, 6.3.14, 6.3.13, 6.3.12, 6.3.11, 6.3.10, 6.3.9, 6.3.8, 6.3.7, 6.3.6, 6.3.5, 6.3.4, 6.3.3, 6.3.2, 6.3.1, 6.3.0, 6.2.6, 6.2.5, 6.2.4, 6.2.3, 6.2.2, 6.2.1, 6.2.0Listed
Weakness

CWE details

No CWE listed

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