CVE-2025-68659 - CVE House
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Status published Medium CVE-2025-68659

Discourse has DoS vulnerability in username change endpoint

Vulnerability Description

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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

References

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Affected Vendor

Affected Software

discourse
Vulnerable Versions:
< 3.5.4, >= 2025.11.0-latest, < 2025.11.2, >= 2025.12.0-latest, < 2025.12.1, >= 2026.1.0-latest, < 2026.1.0

Timeline

Official Publish: January 28th, 2026
Last Modified: January 28th, 2026
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Weaknesses (CWE)

CWE-770

MITRE ATT&CK TTPs

T1499 Endpoint Denial of Service
Impact
T1498 Network Denial of Service
Impact
T1190 Exploit Public-Facing Application
Initial Access
T1562 Impair Defenses
Defense Evasion
T1046 Network Service Discovery
Discovery