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CVE Record

CVE-2021-23428: Directory Traversal

This affects all versions of package elFinder.NetCore. The Path.Combine(...) method is used to create an absolute file path. Due to missing sanitation of the user input and a missing check of the generated path its possible to escape the Files directory via path traversal

HighCVSS 8.6Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2021-23428 is a path traversal flaw in elFinder.NetCore. A remote unauthenticated attacker could cause the file manager to resolve paths outside its intended Files directory, creating a serious risk of sensitive file exposure and limited file impact.

Executive priority

Treat this as high priority where elFinder.NetCore is internet-facing or handles sensitive files. Prioritize inventory, exposure reduction, and vendor-guidance review before deployment changes.

Technical view

The issue stems from using Path.Combine to build absolute paths from insufficiently sanitized user input, without verifying the generated path remains under the configured Files directory. The CVSS 3.1 score is 8.6, with network attack vector, low complexity, no privileges, and no user interaction.

Likely exposure

Exposure is most likely in ASP.NET Core applications that include elFinder.NetCore and expose its file-management routes to users or the internet. The source bundle states all package versions are affected, while the affected version field lists version 0.

Exploitation context

The bundle marks KEV as false, so it does not provide evidence of known active exploitation. CVSS exploit maturity is listed as functional, meaning exploitation is considered practical, but no exploit details should be assumed from the provided sources.

Researcher notes

Evidence is limited to the CVE, Snyk advisory, and upstream repository references. The provided data does not name a patched version or official mitigation. Validate version and route exposure carefully before assigning remediation ownership.

Mitigation direction

  • Inventory applications using elFinder.NetCore.
  • Check Snyk and upstream GitHub for fixed-version or maintainer guidance.
  • Restrict network access to elFinder.NetCore file-management endpoints.
  • Require authentication before any file-management functionality is reachable.
  • Disable or isolate affected functionality if no supported fix is available.
  • Ensure resolved file paths are constrained to the intended file root.

Validation and detection

  • Confirm whether elFinder.NetCore appears in application dependency manifests.
  • Identify public or authenticated routes exposing elFinder.NetCore functionality.
  • Review file-driver configuration for the intended Files directory boundary.
  • Verify code checks canonical resolved paths before file access.
  • Use approved SCA tooling to confirm CVE-2021-23428 detection status.
  • Check logs for unusual file access outside expected application directories.
Prepared
Confidence
high
Sources
5

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.

description · low confidence lookup

File access behavior lookup

The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2021-23428 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
8.6 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L/E:F/RL:U/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
4Source 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
8.6CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L/E:F/RL:U/RC:C3.94.7Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

8.6High
CVSS 3.1 vector shape for CVE-2021-23428Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L/E:F/RL:U/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
n/aelFinder.NetCore0Listed
Weakness

CWE details

No CWE listed

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