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CVE Record

CVE-2021-23394: Remote Code Execution (RCE)

The package studio-42/elfinder before 2.1.58 are vulnerable to Remote Code Execution (RCE) via execution of PHP code in a .phar file. NOTE: This only applies if the server parses .phar files as PHP.

HighCVSS 8.1Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2021-23394 is a high-severity remote code execution issue in studio-42/elfinder before 2.1.58. The risk matters most where elFinder is exposed to users and the web server executes .phar files as PHP. Successful compromise could affect confidentiality, integrity, and availability.

Executive priority

Treat as a priority remediation for any exposed elFinder deployment. The issue can lead to full server compromise, but urgency depends on version, exposure, and whether the server executes .phar files as PHP.

Technical view

The vulnerability concerns elFinder handling of .phar files. Sources state versions before 2.1.58 are vulnerable to PHP code execution via .phar only when the server parses .phar files as PHP. CVSS 3.1 is 8.1 with network attack vector and high impact ratings.

Likely exposure

Likely exposure is web applications embedding studio-42/elfinder before 2.1.58, especially internet-accessible file-manager deployments on PHP servers configured to execute .phar files.

Exploitation context

The source bundle does not show CISA KEV listing or cited evidence of active exploitation. Attack complexity is rated high, and the vulnerability depends on server-side .phar parsing behavior.

Researcher notes

Key uncertainty is environmental: the CVE note limits applicability to servers parsing .phar as PHP. Validate package version, endpoint exposure, authentication, and handler configuration before rating internal risk. Do not assume active exploitation from this bundle.

Mitigation direction

  • Upgrade studio-42/elfinder to version 2.1.58 or later.
  • Check vendor guidance and the referenced fixing commit for deployment-specific details.
  • Disable PHP execution for .phar files where not explicitly required.
  • Restrict elFinder access to trusted, authenticated users only.
  • Review exposed file-manager routes and remove unnecessary public access.

Validation and detection

  • Inventory all applications using studio-42/elfinder.
  • Confirm installed elFinder versions are 2.1.58 or later.
  • Verify web server behavior for .phar file handling.
  • Identify whether elFinder endpoints are internet-accessible.
  • Review logs for unexpected .phar uploads or access patterns.
Prepared
Confidence
high
Sources
7

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

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. 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-2021-23394 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
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

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
6Source 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:H2.25.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

8.1High
CVSS 3.1 vector shape for CVE-2021-23394Attack 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

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/astudio-42/elfinderunspecifiedListed
Weakness

CWE details

No CWE listed

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