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

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-11-10 · updated 2026-06-17
Weakness: CWE-1333

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.

Affected products

discourse: before 3.1.3; before 3.2.0; 3.2.0-beta1, 3.2.0-beta2 — fixed in 3.1.3, 3.2.0

How to fix

Upgrade to a fixed version: discourse 3.1.3, 3.2.0. Check the vendor advisory for mitigations.

References

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