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Fencer Intel
medium 5.1

CVE-2020-11005 json

Internal NCryptDecrypt method could be used externally from WindowsHello library.

published 6y ago modified last mo. also GHSA-wvpv-ffcv-r6cw , EUVD-2020-0397

cvss
5.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits
0
none known

Summary

The WindowsHello open source library (NuGet HaemmerElectronics.SeppPenner.WindowsHello), before version 1.0.4, has a vulnerability where encrypted data could potentially be decrypted without needing authentication. If the library is used to encrypt text and write the output to a txt file, another executable could be able to decrypt the text using the static method NCryptDecrypt from this same library without the need to use Windows Hello Authentication again. This has been patched in version 1.0.4.

Patch / fix

  • nuget HaemmerElectronics.SeppPenner.WindowsHello 1.0.4
  • windowshello_project windowshello 1.0.4

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Exploit prediction

0.23% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 5.1 CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 2.1 AV:L/AC:L/Au:N/C:P/I:N/A:N
GitHub 3.1 5.1 CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
nuget HaemmerElectronics.SeppPenner.WindowsHello
<1.0.4
1.0.4

Affected products

  • SeppPenner WindowsHello

Classification

Weakness
  • CWE-288 Authentication Bypass Using an Alternate Path or Channel
  • CWE-327 Use of a Broken or Risky Cryptographic Algorithm

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.