CVE-2023-36466: Topic Title Validation Skipped When Changing Category in Discourse

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-07-14 · updated 2026-06-17
Weakness: CWE-20

Description

Discourse is an open source discussion platform. When editing a topic, there is a vulnerability that enables a user to bypass the topic title validations for things like title length, number of emojis in title and blank topic titles. The issue is patched in the latest stable, beta and tests-passed version of Discourse.

Affected products

discourse: before 3.0.5; 1.1.0-beta1, 1.1.0-beta2, 1.1.0-beta3, 1.1.0-beta4, 1.1.0-beta5, 1.1.0-beta6 (+203) — fixed in 3.0.5

How to fix

Upgrade to a fixed version: discourse 3.0.5. Check the vendor advisory for mitigations.

References

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