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CVE Record

CVE-2021-26089: An improper symlink following in FortiClient for Mac 6.4.3 and below may allow an non-privileged user to ex...

An improper symlink following in FortiClient for Mac 6.4.3 and below may allow an non-privileged user to execute arbitrary privileged shell commands during installation phase.

MediumCVSS 6.7Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

FortiClient for Mac 6.4.3 and earlier could follow a symlink during installation, letting a local non-admin user cause privileged shell commands to run. This is not a remote internet attack, but it can turn a foothold on a Mac into full system compromise during an install or upgrade workflow.

Executive priority

Treat as a targeted endpoint privilege-escalation risk, not an internet-wide emergency. Remediate during normal vulnerability cycles, faster for high-value Macs or environments with weak local install controls.

Technical view

The issue is improper symlink following in FortiClientMac installation handling. CVSS 3.1 is 6.7: local attack, high complexity, low privileges, user interaction required, with high confidentiality, integrity, and availability impact if successful.

Likely exposure

Exposure is limited to macOS systems running Fortinet FortiClientMac 6.4.3 or below, especially where users can install or update the client locally.

Exploitation context

The provided bundle does not show active exploitation, and KEV is false. Exploitation requires local access, low privileges, user interaction, and a vulnerable installation phase, reducing scale but increasing concern on already-compromised endpoints.

Researcher notes

Evidence is limited to the CVE description, affected version statement, CVSS vector, Fortinet advisory reference, and ZDI reference. No exploit details, proof of active exploitation, or fixed version text is included in the supplied bundle.

Mitigation direction

  • Inventory macOS endpoints for FortiClientMac 6.4.3 and earlier.
  • Review Fortinet advisory FG-IR-21-022 for supported fixed-version guidance.
  • Prioritize upgrades on shared, developer, and administrator workstations.
  • Restrict who can install or modify endpoint security software.
  • Monitor vendor guidance for any updated remediation instructions.

Validation and detection

  • Confirm installed FortiClientMac versions across managed macOS assets.
  • Identify endpoints where local users can trigger client installation or upgrade.
  • Check endpoint logs for suspicious privileged command execution around installs.
  • Verify remediation status against Fortinet’s advisory, not assumptions.
  • Document exceptions for systems that cannot be upgraded promptly.
Prepared
Confidence
medium
Sources
4

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-2021-26089 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:H/PR:L/UI:R/S:U/C:H/I:H/A:H

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
3Source 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:H/PR:L/UI:R/S:U/C:H/I:H/A:H0.85.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

6.7Medium
CVSS 3.1 vector shape for CVE-2021-26089Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H

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 FortiClientMacFortiClientMac 6.4.3 and belowListed
Weakness

CWE details

No CWE listed

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