Is CVE-2026-27737 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-27737 being exploited in the wild.

How severe is CVE-2026-27737?

Medium severity, with a CVSS score of 6.5, published 18 May 2026.

Which products and versions are affected?

BigBlueButton Bbb-Playback < 5.4.3; BigBlueButton < 3.0.19; Blindside Networks Scalelite < 1.7.0.

Is there a fix for CVE-2026-27737?

A patch was published on 2026-05-18: Fix confirmed in version 3.0.19 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-27737 attacked?

It is attacked over the network, in a web application.

Am I affected by CVE-2026-27737?

Check whether you run BigBlueButton Bbb-Playback, BigBlueButton or Blindside Networks Scalelite at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-27737: BigBlueButton stored XSS in recording playback chat

Q: Is there a fix for CVE-2026-27737?

A patch was published on 2026-05-18: Fix confirmed in version 3.0.19 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-27737 attacked?

It is attacked over the network, in a web application.

Q: Am I affected by CVE-2026-27737?

Check whether you run BigBlueButton Bbb-Playback, BigBlueButton or Blindside Networks Scalelite at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-27737 · Severity: medium · CVSS 6.5 · Published 2026-05-18

BigBlueButton is an open-source virtual classroom platform used for online learning and meetings. A security flaw in the recording playback feature allowed malicious users to insert harmful scripts into the public chat during a live session. These scripts would then execute automatically whenever any student or instructor later replayed the recording, potentially allowing the attacker to hijack sessions or steal sensitive information.

Technologies: BigBlueButton. Vendors: BigBlueButton.

Quick answers

Is CVE-2026-27737 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-27737 being exploited in the wild.
How severe is CVE-2026-27737?: Medium severity, with a CVSS score of 6.5, published 18 May 2026.
Which products and versions are affected?: BigBlueButton Bbb-Playback < 5.4.3; BigBlueButton < 3.0.19; Blindside Networks Scalelite < 1.7.0.
Is there a fix for CVE-2026-27737?: A patch was published on 2026-05-18: Fix confirmed in version 3.0.19 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-27737 attacked?: It is attacked over the network, in a web application.
Am I affected by CVE-2026-27737?: Check whether you run BigBlueButton Bbb-Playback, BigBlueButton or Blindside Networks Scalelite at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A stored Cross-Site Scripting (XSS) vulnerability exists in the bbb-playback component of BigBlueButton. The root cause is a failure to sanitize user-provided input in the public chat module before it is rendered during recording playback in the presentation format. An attacker with basic participant privileges can inject malicious JavaScript into the chat during a live session. This script is then persisted in the recording and executes in the context of any user who later views the recording playback. The issue is resolved in BigBlueButton version 3.0.19 (which includes bbb-playback 5.4.3) and Scalelite version 1.7.0.

Affected products

BigBlueButton BigBlueButton < 3.0.19
BigBlueButton bbb-playback < 5.4.3
Blindside Networks Scalelite < 1.7.0

Timeline

2026-05-12: advisory: GitHub Security Advisory published
2026-05-18: disclosed: NVD publication date
2026-05-18: patched: Fix confirmed in version 3.0.19

References

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