CVE-2021-23427Public exploitNetwork attack vector

Arbitrary file overwrite via unchecked ZIP paths

Published Sep 1, 2021 · Updated Sep 16, 2024

Path traversal in Matt Gordon elFinder.NetCore 1.3.5 and earlier allows remote attackers to write files outside the extraction directory. FileSystemDriver.ExtractAsync combines rootPath with each untrusted ZIP entry name and calls ExtractToFile without verifying that the resolved path remains beneath the intended root. An application must expose archive upload and extraction to the attacker; successful traversal overwrites files writable by the server process.

CVSS severity9.8
Critical
EPSS probability1.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Matt Gordon elFinder.NetCore 1.3.5 and earlier allows remote attackers to write files outside the extraction directory. FileSystemDriver.ExtractAsync combines rootPath with each untrusted ZIP entry name and calls ExtractToFile without verifying that the resolved path remains beneath the intended root. An application must expose archive upload and extraction to the attacker; successful traversal overwrites files writable by the server process.

The record

CVE
CVE-2021-23427
Published
Sep 1, 2021
Updated
Sep 16, 2024
Vendor
Matt Gordon
Product
elFinder.NetCore
Classifications
CWE-22, CWE-20, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 1, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=0 <unspecified

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Matt Gordon · elFinder.NetCoreversion=0 <unspecified

Published CVSS scores

8.6SnykCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
9.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST National Vulnerability DatabaseAV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-20Improper Input Validation
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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