CVE-2025-55200Network attack vector

Privileged-session script execution via unescaped usernames

Published Oct 9, 2025 · Updated Oct 9, 2025

Stored XSS in BigBlueButton before 3.0.13 allows remote authenticated users to execute JavaScript through a crafted username in Shared Notes. The bbb-pads integration passes usernames into Etherpad without HTML escaping, allowing markup to be rendered when an editor appears in Shared Notes. Exploitation requires a low-privileged meeting user to edit notes and a higher-privileged user to open the page, exposing that user's browser session to attacker-controlled script.

CVSS severity7.1
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in BigBlueButton before 3.0.13 allows remote authenticated users to execute JavaScript through a crafted username in Shared Notes. The bbb-pads integration passes usernames into Etherpad without HTML escaping, allowing markup to be rendered when an editor appears in Shared Notes. Exploitation requires a low-privileged meeting user to edit notes and a higher-privileged user to open the page, exposing that user's browser session to attacker-controlled script.

The record

CVE
CVE-2025-55200
Published
Oct 9, 2025
Updated
Oct 9, 2025
Vendor
BigBlueButton Inc.
Product
BigBlueButton
Classifications
CWE-80, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 9, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 9, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.0.13

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

BigBlueButton Inc. · BigBlueButtonversion=< 3.0.13

Published CVSS scores

7.1GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-80Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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