CVE-2025-68659: Discourse has DoS vulnerability in username change endpoint
Discourse is an open source discussion platform. Versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0 have an application level denial of service vulnerabilityin the username change functionality at try.discourse.org. The vulnerability allows attackers to cause noticeable server delays and resource exhaustion by sending large JSON payloads to the username preference endpoint PUT /u//preferences/username, resulting in degraded performance for other users and endpoints. This issue is patched in versions 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0. No known workarounds are available.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2025-68659?
CVE-2025-68659 is classified as a denial of service vulnerability affecting the username change functionality in Discourse.
How do I fix CVE-2025-68659?
To fix CVE-2025-68659, upgrade to Discourse version 3.5.4 or later, 2025.11.2 or later, 2025.12.1 or later, or 2026.1.0.
Which versions of Discourse are affected by CVE-2025-68659?
Versions of Discourse prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0 are affected by CVE-2025-68659.
What impact does CVE-2025-68659 have on Discourse?
CVE-2025-68659 can lead to application-level denial of service, causing disruptions in service availability.
Is there a workaround for CVE-2025-68659?
There is no specific workaround for CVE-2025-68659; the recommended solution is to apply the security update.