LiveActive security incident?Get immediate response
CVE Record

CVE-2021-24019: An insufficient session expiration vulnerability [CWE- 613] in FortiClientEMS versions 6.4.2 and below, 6.2...

An insufficient session expiration vulnerability [CWE- 613] in FortiClientEMS versions 6.4.2 and below, 6.2.8 and below may allow an attacker to reuse the unexpired admin user session IDs to gain admin privileges, should the attacker be able to obtain that session ID (via other, hypothetical attacks)

HighCVSS 8.1Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2021-24019 affects Fortinet FortiClientEMS. Admin sessions may not expire properly, so a stolen unexpired admin session ID could be reused to gain administrator access. The source states the attacker must first obtain the session ID through another attack, which raises difficulty but leaves high business impact if successful.

Executive priority

Prioritize remediation for any affected FortiClientEMS deployment because successful exploitation could grant administrator control. The attack requires a stolen session ID, so urgency depends on exposure of the admin interface and confidence that session IDs are protected.

Technical view

The issue is an insufficient session expiration flaw, CWE-613, in FortiClientEMS 6.4.2 and below and 6.2.8 and below. Reuse of an unexpired admin session ID may grant admin privileges. CVSS 3.1 is 8.1 high, network reachable, no privileges, no user interaction, high attack complexity, with high confidentiality, integrity, and availability impact.

Likely exposure

Exposure is limited to organizations running the listed FortiClientEMS versions: 6.4.0 through 6.4.2 and 6.2.0 through 6.2.8. Risk is highest where administrative access is reachable over broad networks or where session IDs could be captured by separate weaknesses.

Exploitation context

The bundle does not cite CISA KEV listing or confirmed active exploitation. The described attack depends on obtaining a valid admin session ID through other hypothetical attacks, so this is not a standalone initial-access finding based on the provided evidence.

Researcher notes

Evidence is concise and vendor-centered. The key constraint is prerequisite session ID acquisition, reflected by high attack complexity. Do not treat this as confirmed exploited from the provided sources. Validation should focus on version exposure, admin surface reachability, and session theft indicators.

Mitigation direction

  • Check Fortinet advisory FG-IR-20-072 for vendor-approved fixes or mitigations.
  • Upgrade FortiClientEMS according to Fortinet guidance for affected versions.
  • Restrict FortiClientEMS administrative access to trusted networks and administrators.
  • Invalidate active admin sessions after remediation or suspected session exposure.
  • Review related controls that could expose session IDs, such as insecure transport or logging.

Validation and detection

  • Inventory all FortiClientEMS deployments and record exact versions.
  • Confirm whether any instance runs 6.4.2 or below, or 6.2.8 or below.
  • Review admin access paths for unnecessary network exposure.
  • Check whether session-management settings and remediation match Fortinet guidance.
  • Look for evidence of unusual admin activity around session reuse timelines.
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.

cve · low confidence lookup

CVE-2021-24019 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
8.1 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/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
8.1CVSS 3.1HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:X/RC:X2.25.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

8.1High
CVSS 3.1 vector shape for CVE-2021-24019Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/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 FortiClientEMSFortiClientEMS 6.4.2, 6.4.1, 6.4.0, 6.2.8, 6.2.7, 6.2.6, 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.