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CVE Record

CVE-2021-43080: An improper neutralization of input during web page generation vulnerability [CWE-79] in FortiOS version 7....

An improper neutralization of input during web page generation vulnerability [CWE-79] in FortiOS version 7.2.0, version 6.4.0 through 6.4.9, version 7.0.0 through 7.0.5 may allow an authenticated attacker to perform a stored cross site scripting (XSS) attack through the URI parameter via the Threat Feed IP address section of the Security Fabric External connectors.

MediumCVSS 4.6Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-43080 is a stored cross-site scripting issue in Fortinet FortiOS. An authenticated attacker could save malicious content through a Threat Feed IP address URI field, causing script execution when another user views the affected page. Business impact is usually limited but can affect administrator trust and session integrity.

Executive priority

Prioritize remediation in normal patch cycles, faster for internet-reachable or widely delegated FortiOS management environments. The issue requires authentication and user interaction, but FortiOS is security infrastructure, so avoid leaving affected management planes unreviewed.

Technical view

FortiOS 7.2.0, 7.0.0 through 7.0.5, and 6.4.0 through 6.4.9 improperly neutralize web output in the Security Fabric External connectors Threat Feed IP address section. The CVSS 3.1 score is 4.6 with network access, low attack complexity, low privileges, and required user interaction.

Likely exposure

Exposure is limited to organizations running the listed FortiOS versions where authenticated users can access the relevant Threat Feed IP address connector workflow. Devices with broadly accessible management interfaces or many delegated administrators have higher practical risk.

Exploitation context

The source bundle does not identify active exploitation, and the CVE is not marked as CISA KEV. The attacker must already authenticate and still needs a victim user to interact with the stored content. Treat this as a management-plane integrity risk, not unauthenticated remote compromise.

Researcher notes

Evidence supports stored XSS through the URI parameter in the Threat Feed IP address section. The provided data does not include exploit availability, proof-of-concept details, or named fixed versions. Do not expand scope beyond FortiOS and the affected release ranges listed.

Mitigation direction

  • Check Fortinet advisory FG-IR-21-222 for vendor-approved upgrade or remediation guidance.
  • Inventory FortiOS versions and identify systems running the listed affected releases.
  • Restrict FortiOS management access to trusted networks and authorized administrators.
  • Review delegated administrator permissions for Security Fabric External connector configuration.

Validation and detection

  • Confirm FortiOS version against the affected version list in the CVE record.
  • Check whether Security Fabric External connectors and Threat Feed IP address entries are used.
  • Review administrative users with permission to create or edit external connectors.
  • Look for vendor advisory updates before closing remediation tracking.
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-2021-43080 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
4.6 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N/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
4.6CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N/E:F/RL:X/RC:X2.12.5Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

4.6Medium
CVSS 3.1 vector shape for CVE-2021-43080Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N/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
FortinetFortinet FortiOSFortiOS 7.2.0, 7.0.5, 7.0.4, 7.0.3, 7.0.2, 7.0.1, 7.0.0, 6.4.9, 6.4.8, 6.4.7, 6.4.6, 6.4.5, 6.4.4, 6.4.3, 6.4.2, 6.4.1, 6.4.0Listed
Weakness

CWE details

No CWE listed

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