Information disclosure in Zoom
CVE-2021-28133
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.
Vulnerability class: Information Disclosure
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.163 (96.9th percentile), scored .
Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 97th percentile — 96.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.163 · newest: 0.163 · change: 0.000
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2020-044.txt (Third Party Advisory)
- zoom.us/trust/security/security-bulletin (Vendor Advisory)
- www.youtube.com/watch (Third Party Advisory)
- www.syss.de/pentest-blog/syss-2020-044-sicherheitsproblem-in-screen-sharing-fun… (Third Party Advisory)
- seclists.org/fulldisclosure/2021/Mar/48 (mailing-list, Third Party Advisory)
- thehackernews.com/2021/03/new-zoom-screen-sharing-bug-lets-other.html (Third Party Advisory)
- packetstormsecurity.com/files/161897/Zoom-5.4.3-54779.1115-5.5.4-13142.0301-Inf… (Third Party Advisory)
Frequently asked questions
- What is CVE-2021-28133?
- CVE-2021-28133 is a medium-severity vulnerability in Zoom, classified under Information Disclosure. CVSS score: 4.3/10. Published 2021-03-18.
- How severe is CVE-2021-28133?
- Medium severity. CVSS v3 base score is 4.3 out of 10.
- Is CVE-2021-28133 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.