What is CVE-2025-68659?

CVE-2025-68659 is a medium-severity vulnerability in Discourse, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 4.3/10. Published 2026-01-28.

How severe is CVE-2025-68659?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Resource exhaustion in Discourse

CVE-2025-68659

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.

EPSS: 0.002 (12.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L.

Affected products

Discourse — versions >= 2026.1.0-latest, < 2026.1.0, >= 2025.12.0-latest, < 2025.12.1, < 3.5.4

Weakness classification (CWE)

CWE-770 — Allocation of Resources Without Limits or Throttling

References

security-advisories@github.com (x_refsource_CONFIRM, Third Party Advisory)

Frequently asked questions

What is CVE-2025-68659?: CVE-2025-68659 is a medium-severity vulnerability in Discourse, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 4.3/10. Published 2026-01-28.
How severe is CVE-2025-68659?: Medium severity. CVSS v3 base score is 4.3 out of 10.