Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-55491— BigBlueButton: Stored XSS in Screenshare Recording Playback via Unescaped Meeting Name

Quick assessment

Affected
bigbluebutton bigbluebutton
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

BigBlueButton是BigBlueButton社区开源的一款视频会议软件。 BigBlueButton 3.0.29之前版本存在跨站脚本漏洞，该漏洞源于生成屏幕共享播放格式时未对record-and-playback/screenshare/playback/index.html.erb中的meetingName参数进行转义，可能导致低权限用户存储嵌入脚本的特制会议名称，当其他用户重放录制时脚本在浏览器中执行。

CVSS 5.4 · Medium EPSS 0.29% · P20

Affected Version Matrix 1

VendorProduct Version RangeStatus
bigbluebutton bigbluebutton < 3.0.29 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-55491

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
BigBlueButton: Stored XSS in Screenshare Recording Playback via Unescaped Meeting Name
Source: CVE Program / CVE List V5
Vulnerability Description
BigBlueButton is an open-source virtual classroom. Prior to 3.0.29, BigBlueButton failed to escape meetingName in record-and-playback/screenshare/playback/index.html.erb when generating the screenshare playback format. A low-privileged user could store a crafted meeting name that embedded script content, and the script executed in another user's browser when that user replayed the recording. This issue is fixed in version 3.0.29.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
在Web页面生成时对输入的转义处理不恰当(跨站脚本)
Source: CVE Program / CVE List V5
Vulnerability Title
BigBlueButton 跨站脚本漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
BigBlueButton是BigBlueButton社区开源的一款视频会议软件。 BigBlueButton 3.0.29之前版本存在跨站脚本漏洞，该漏洞源于生成屏幕共享播放格式时未对record-and-playback/screenshare/playback/index.html.erb中的meetingName参数进行转义，可能导致低权限用户存储嵌入脚本的特制会议名称，当其他用户重放录制时脚本在浏览器中执行。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
bigbluebutton bigbluebutton < 3.0.29 -

II. Public POCs for CVE-2026-55491

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-55491

请登录查看更多情报信息。

Patches & Fixes for CVE-2026-55491 (1)

Vendor Advisories for CVE-2026-55491 (1)

Vendor Pages for CVE-2026-55491 (1)

Same Patch Batch · bigbluebutton · 2026-08-20 · 4 CVEs total

CVE-2026-46682 8.5 HIGH BigBlueButton: Blind SQL Injection AUTH (Moderator)
CVE-2026-46355 7.1 HIGH BigBlueButton: Unauthenticated Session Hijack via Exposed /bigbluebutton/api/handleJoinExi
CVE-2026-55489 4.9 MEDIUM BigBlueButton: IDOR on BBB through /api/graphql via POST parameter "presentationId" leads

IV. Related Vulnerabilities

Same product: bigbluebutton
Same vendor: bigbluebutton
Same weakness: CWE-79

V. Comments for CVE-2026-55491

No comments yet

Leave a comment