CVE-2025-54411

Browser script execution via unsanitized display name

Published Aug 19, 2025 · Updated Aug 19, 2025

Cross-site scripting in the Discourse welcome banner before 3.5.0.beta8 allows local users to execute script in an administrator's browser. The WelcomeBanner component passes currentUser.name through preferred_display_name without sanitizing HTML before the logged-in header is rendered. The user must have a malformed display name, and execution reaches another account only when an administrator impersonates that user.

CVSS severity2.4
Low
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in the Discourse welcome banner before 3.5.0.beta8 allows local users to execute script in an administrator's browser. The WelcomeBanner component passes currentUser.name through preferred_display_name without sanitizing HTML before the logged-in header is rendered. The user must have a malformed display name, and execution reaches another account only when an administrator impersonates that user.

The record

CVE
CVE-2025-54411
Published
Aug 19, 2025
Updated
Aug 19, 2025
Vendor
Discourse
Product
Discourse
Classifications
CWE-80, T1059.007
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 19, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 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=< 3.5.0.beta8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Discourse · Discourseversion=< 3.5.0.beta8

Published CVSS scores

2.4GitHubCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA: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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-80Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
T1059.007JavaScript/JScript

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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