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Fencer Vulns
medium 4.3

CVE-2021-28133 json

Zoom through 5.5.4 sometimes allows attackers to read private information on a participant's screen, even though the participant never atte…

published 2021-03-18 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-14832

cvss
4.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
19.9%
EPSS 19.9% chance of exploitation in 30 days, percentile 97%
public exploits
0
none known

Summary

Zoom through 5.5.4 sometimes allows attackers to read private information on a participant's screen, even though the participant never attempted to share the private part of their screen. When a user shares a specific application window via the Share Screen functionality, other meeting participants can briefly see contents of other application windows that were explicitly not shared. The contents of these other windows can (for instance) be seen for a short period of time when they overlay the shared window and get into focus. (An attacker can, of course, use a separate screen-recorder application, unsupported by Zoom, to save all such contents for later replays and analysis.) Depending on the unintentionally shared data, this short exposure of screen contents may be a more or less severe security issue.

Exploit prediction

19.93% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N

Classification

Weakness
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

References

Sources

Fencer Vulns 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.