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NVD / CVE Program· CNA snyk

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

Noroxi assessment

Priority: Plan (action score 45/100)

  • A ready-made attack module is public (Nuclei); exploiting it takes no special expertise.
  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 18.9% (FIRST EPSS); higher than 97.3% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: studio-42/elfinder (Packagist) 2.1.58.

Add it to your regular patch cycle. Upgrade to studio-42/elfinder (Packagist) 2.1.58 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

CriticalCVSS 9.8 · v3.1—Proof of concept Fix available
Published
Jun 13, 2021
Updated
Jun 16, 2026
EPSS
18.9% · 97th percentile

Report tools

JSON

Action score

45

Plan

Add it to your regular patch cycle.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
6 / 30 · 18.9%

CNA vs NVD score

NVD
9.8
CNA · snyk
8.1
1.7 point gap

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-23394

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
std42elfinder

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • std42 elfinderbefore 2.1.58

Versions reported by the vendor

Affected version ranges reported by the assigning authority (snyk). Independent of NVD's CPE analysis and usually ahead of it.

  • n/a studio-42/elfinder

    • unspecified and later · before 2.1.58affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Packagiststudio-42/elfinderbefore 2.1.582.1.58

Same product

std42: all records

Other highest-scoring records for the same primary product.

  • CVE-2019-9194elFinder before 2.1.48 has a command injection vulnerability in the PHP connector.
    68This week
  • CVE-2021-32682Multiple vulnerabilities leading to RCE
    60This week
  • CVE-2021-43421A File Upload vulnerability exists in Studio-42 elFinder 2.0.4 to 2.1.59 via connector.minimal.php, which allows a remote malicious user to…
    52Plan

Published before and after this one in the same product

  • ← EarlierCVE-2019-5884Jan 10, 2019 · php/elFinder.class.php in elFinder before 2.1.45 leaks information if PHP's curl extension is enabled and safe_mode or open_basedir is not…
    23Monitor
  • ← EarlierCVE-2019-6257Jan 14, 2019 · A Server Side Request Forgery (SSRF) vulnerability in elFinder before 2.1.46 could allow a malicious user to access the content of internal…
    30Monitor
  • Later →CVE-2021-45919Feb 8, 2022 · Studio 42 elFinder through 2.1.31 allows XSS via an SVG document.
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Packagist:studio-42/elfinder2.1.58Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Nuclei detection template ×1
  • Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Nuclei detection templateNuclei template CVE-2021-23394 —
Proof-of-concept repository on GitHubstars:02025-11-30

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoC+1631 d
  3. TodayNov 11, 2026+1977 d

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-434 · Unrestricted Upload of File with Dangerous Type

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records