CVE-2021-26421
mediumpriority · track · 23EPSS 0.014 · 73 %ileEURUUSgrimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
1.41% (73rd) EPSS
CVSS 5.8 · medium
Who says so?
4 sources
cnnvd · enisa_euvd · fstec_bdu · nvd
EPSS · scored 2026-10-27
Skype for Business and Lync Spoofing Vulnerability
01
cvss
Technical severity, 0–10. One row per scoring source.
7.1
010
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4.9–7.1
v3.17.1highCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:Nsecondary · NVD / NIST USexploitability 2.8 · impact 4.2
v3.16.5mediumCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:L/A:Nsecondary · secure@microsoft.com USexploitability 1.3 · impact 4.7
02
weaknesses
The CWE weakness classes this flaw belongs to.
03
affected products (6)
Products and version ranges known to be affected.
- microsoft skype for business server= 2015nvdUScpe:2.3:a:microsoft:skype_for_business_server:*:*:*:*:*:*:*:*
04
also known as (4)
Other names and identifiers for this entity.
05
sources
Which sources assert this record, and when.
06
references (6)
External citations — patches, advisories, analysis.
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26421cnnvd
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26421cnnvd
- https://vigilance.fr/vulnerability/Microsoft-Lync-Skype-vulnerabilities-of-May-2021-35381cnnvd
- https://www.cybersecurity-help.cz/vdb/SB2021051122cnnvd
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26421enisa_euvd
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26421PatchVendor Advisorynvd
scry
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