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Fencer Intel
high 8.6

CVE-2021-23427 json

Arbitrary File Write via Archive Extraction (Zip Slip)

published 5y ago modified 4mo ago also GHSA-wmpm-fq7r-jq56 , EUVD-2021-2127

cvss
8.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 73%
public exploits
0
none known

Summary

This affects all versions of package elFinder.NetCore. The ExtractAsync function within the FileSystem is vulnerable to arbitrary extraction due to insufficient validation.

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Exploit prediction

1.43% chance of exploitation in the next 30 days, higher than 73% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • snyk.io https://snyk.io/vuln/SNYK-DOTNET-ELFINDERNETCORE-1567778 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.6 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
CNA 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
GitHub 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
nuget elFinder.NetCore
<=1.3.5
 no fix listed

Affected products

  • n/a elFinder.NetCore

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory
  • CWE-20 Improper Input Validation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.