What is CVE-2020-28953?

CVE-2020-28953 is a medium-severity vulnerability in Bigbluebutton. CVSS score: 4.3/10. Published 2020-11-19.

How severe is CVE-2020-28953?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Vulnerability in Bigbluebutton

CVE-2020-28953

In BigBlueButton before 2.2.29, a user can vote more than once in a single poll.

Published 2020-11-19 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.007 (51.3th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 51.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Bigbluebutton

References

github.com/bigbluebutton/bigbluebutton/compare/v2.2.28...v2.2.29 (Third Party Advisory, Release Notes)
github.com/bigbluebutton/bigbluebutton/commit/d2cb02b3bd670265c6b1ba003f87fc261… (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2020-28953?: CVE-2020-28953 is a medium-severity vulnerability in Bigbluebutton. CVSS score: 4.3/10. Published 2020-11-19.
How severe is CVE-2020-28953?: Medium severity. CVSS v3 base score is 4.3 out of 10.