CVE-2021-28133
Zoom through 5.5.4 sometimes allows attackers to read private information on a participant's...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
4.3
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.
- Record
CVE-2021-28133- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:P/I:N/A:N - Weakness
- CWE-200
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2021-28133- Updated
- 2026-11-02
EUVDEUVD-2021-14832 No score
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.
- Record
EUVD-2021-14832- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-qj56-qx26-7qr8 No score
Zoom through 5.5.4 sometimes allows attackers to read private information on a participant's...
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.
- Record
GHSA-qj56-qx26-7qr8- Weakness
- CWE-200
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-28133 is a medium vulnerability (CVSS 4.3) in Zoom, published March 18, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 19.9%, the 97th percentile. No source names a fixed version.
References
syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2020-044.txt
zoom.us/trust/security/security-bulletin
youtube.com/watch?v=SonmmgQlLzg
syss.de/pentest-blog/syss-2020-044-sicherheitsproblem-in-screen-sharing-funktionalitaet-von-zoom-cve-2021-28133
seclists.org/fulldisclosure/2021/Mar/48
thehackernews.com/2021/03/new-zoom-screen-sharing-bug-lets-other.html
packetstormsecurity.com/files/161897/Zoom-5.4.3-54779.1115-5.5.4-13142.0301-Information-Disclosure.html
nvd.nist.gov/vuln/detail/CVE-2021-28133
github.com/advisories/GHSA-qj56-qx26-7qr8