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CVE Record

CVE-2021-26096: Multiple instances of heap-based buffer overflow in the command shell of FortiSandbox before 4.0.0 may allo...

Multiple instances of heap-based buffer overflow in the command shell of FortiSandbox before 4.0.0 may allow an authenticated attacker to manipulate memory and alter its content by means of specifically crafted command line arguments.

MediumCVSS 6.4Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-26096 is a FortiSandbox command-shell memory-safety flaw. An authenticated attacker could use specially crafted command-line arguments to manipulate memory, potentially affecting data integrity and service stability. The issue affects FortiSandbox versions before 4.0.0.

Executive priority

Prioritize remediation in normal vulnerability management cycles, faster where FortiSandbox administration is reachable from broad networks or many users have access. The issue is not currently evidenced as actively exploited in the provided sources.

Technical view

The sources describe multiple heap-based buffer overflows in FortiSandbox command shell handling before version 4.0.0. CVSS 3.1 is 6.4: network reachable, high complexity, low privileges required, no user interaction, with low confidentiality, high integrity, and low availability impact.

Likely exposure

Exposure is likely limited to organizations running FortiSandbox before 4.0.0 where authenticated users can access the affected command shell path. Risk increases if low-privilege accounts are broadly available or administrative interfaces are reachable from less-trusted networks.

Exploitation context

The provided sources do not show CISA KEV listing or active exploitation evidence. Exploitation requires authentication and high attack complexity, but successful abuse could alter memory content through crafted command-line arguments.

Researcher notes

Evidence is concise: the CVE record identifies affected versions, attack prerequisites, and impact through the CVSS vector. The source bundle does not provide exploit details, proof of exploitation, or compensating controls beyond the vendor advisory reference.

Mitigation direction

  • Upgrade affected FortiSandbox deployments to 4.0.0 or a vendor-recommended later release.
  • Review Fortinet advisory FG-IR-20-188 for exact vendor remediation guidance.
  • Restrict FortiSandbox management and shell access to trusted administrators only.
  • Monitor authenticated FortiSandbox activity for unusual command-shell usage.

Validation and detection

  • Inventory all FortiSandbox instances and record installed versions.
  • Confirm no production system is running a version before 4.0.0.
  • Review account permissions for users with FortiSandbox command-shell access.
  • Check logs for unusual authenticated command-shell activity around exposed systems.
Prepared
Confidence
medium
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-2021-26096 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:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:L/E:X/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
6.4CVSS 3.1MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:L/E:X/RL:X/RC:X1.64.7Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

6.4Medium
CVSS 3.1 vector shape for CVE-2021-26096Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:L/E:X/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 FortiSandboxFortiSandbox before 4.0.0Listed
Weakness

CWE details

No CWE listed

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