How severe is CVE-2020-28953?

CVE-2020-28953 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2020-28953 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-28953?

CVE-2020-28953 affects Bigbluebutton. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-28953?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-28953 published?

CVE-2020-28953 was published on 2020-11-19 and last updated on 2026-06-17.

CVE-2020-28953

CVE-2020-28953 is a medium-severity vulnerability in Bigbluebutton with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.0
EPSS exploit prediction: 1% (48th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Bigbluebutton
Published: 2020-11-19
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is CVE-2020-28953?: In BigBlueButton before 2.2.29, a user can vote more than once in a single poll.
How severe is CVE-2020-28953?: CVE-2020-28953 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2020-28953 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-28953?: CVE-2020-28953 affects Bigbluebutton. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-28953?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-28953 published?: CVE-2020-28953 was published on 2020-11-19 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:bigbluebutton:bigbluebutton:*:*:*:*:*:*:*:*

More vulnerabilities in Bigbluebutton

CVE-2020-27602 — Critical (CVSS 9.8): BigBlueButton before 2.2.7 does not have a protection mechanism for separator injection in meetingId, userId, and…
CVE-2020-27605 — Critical (CVSS 9.8): BigBlueButton through 2.2.28 uses Ghostscript for processing of uploaded EPS documents, and consequently may be subject…
CVE-2020-12443 — Critical (CVSS 9.8): BigBlueButton before 2.2.6 allows remote attackers to read arbitrary files because the presfilename (lowercase) value…
CVE-2020-27613 — High (CVSS 8.4): The installation procedure in BigBlueButton before 2.2.28 (or earlier) uses ClueCon as the FreeSWITCH password, which…
CVE-2025-61602 — High (CVSS 7.5): BigBlueButton is an open-source virtual classroom. A denial-of-service (DoS) vulnerability in versions prior to 3.0.13…
CVE-2025-61601 — High (CVSS 7.5): BigBlueButton is an open-source virtual classroom. A Denial of Service (DoS) vulnerability in versions prior to 3.0.13…

All CVEs affecting Bigbluebutton →