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Fencer Intel
high 7.1

CVE-2021-26421 json

Skype for Business and Lync Spoofing Vulnerability

published 5y ago modified 4mo ago also EUVD-2021-13227

cvss
7.1
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 72%
public exploits
0
none known

Summary

Skype for Business and Lync Spoofing Vulnerability

Patch / fix

  • Microsoft Skype for Business Server 2015 CU11 2046.369
  • Microsoft Microsoft Lync Server 2013 CU10 8308.1144

Is CVE-2021-26421 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

1.41% chance of exploitation in the next 30 days, higher than 72% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:L/A:N/E:U/RL:O/RC:C
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:L/A:N
CNA 3.1 7.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
NVD 2.0 5.8 AV:N/AC:M/Au:N/C:P/I:P/A:N

Affected products

  • Microsoft Skype for Business Server 2015 CU11
  • Microsoft Microsoft Lync Server 2013 CU10

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.