How severe is CVE-2021-23428?

CVE-2021-23428 has a CVSS score of 8.6/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-23428?

CVE-2021-23428 affects the following packages: elFinder.NetCore (NuGet). Ecosystems affected: NuGet.

How do I fix CVE-2021-23428?

No patched version of elFinder.NetCore has shipped for CVE-2021-23428 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

How do I detect CVE-2021-23428 in my NuGet dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for elFinder.NetCore, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-23428 if there is no patch (or I can't update yet)?

Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Is CVE-2021-23428 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-23428 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-23428?

CVE-2021-23428 has an EPSS (Exploit Prediction Scoring System) score of 1.7%, placing it in the 76th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-23428?

CVE-2021-23428 is classified as Path Traversal (CWE-22). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2021-23428 published, and has it been updated?

CVE-2021-23428 was published on September 2, 2021 and was last updated on March 13, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

.NET

.NET NuGet

Not in CISA KEV

HIGH severity

CVE-2021-23428 — elFinder.NetCore

HIGH

CVE-2021-23428 is a high-severity (CVSS 8.6) Path Traversal vulnerability in elFinder.NetCore. No vendor fix is recorded yet; mitigation options are listed below.

Path traversal in elFinder.NetCore

Published

Sep 2, 2021

Updated

Mar 13, 2026

Affected

1 pkg

Patched

See advisory

Exploits

None indexed

Exploitation data as of Oct 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.7%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs76th percentile — riskier than 76% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-23428 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

.NETelFinder.NetCore

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.

Description

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

Affected Packages

1 total

Ecosystem	Package	Vulnerable range	Fix
.NETNuGet	`elFinder.NetCore`	all versions	No fix

Affected Products

1 product · 1 configurations

Application

elfinder.netcoreelfinder.netcore_project

all

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for elFinder.NetCore, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of elFinder.NetCore has shipped for CVE-2021-23428 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-23428 in your dependencies?

Find it across NuGet, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

8.6/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

Low

Availability

Low

Raw vector

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

CWE Classification

CWE-22Path Traversal

Weaponization

No known public exploit tooling found.

Timeline

Disclosed

Sep 2, 2021

Last updated

Mar 13, 2026

Identifiers

CVE-2021-23428

References

Advisorynvd.nist.gov Webgithub.com Webgithub.com Websnyk.io Packagegithub.com

Related vulnerabilities

Also affects elFinder.NetCore

This CVE is high severity; 1 of 1 other CVE affecting elFinder.NetCore is rated as high or higher (top: critical).

CVE-2021-23427

Same weakness: CWE-22

This CVE is high severity; 5 of 7 other CVEs with CWE-22 are rated as high or higher (top: critical).

CVE-2026-63445CVE-2026-72697CVE-2026-74907CVE-2026-63225CVE-2026-86071CVE-2026-45140CVE-2026-72695Browse all CWE-22

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedMar 13, 2026