CVE-2026-72728 PUBLISHED

Discourse: Onebox iframe origin allowlist enforces URL authority boundary

Assigner: GitHub_M
Reserved: 10.08.2026 Published: 10.08.2026 Updated: 10.08.2026

Discourse is an open-source discussion platform. Prior to 2026.1.7, an authenticated user could submit specially formed URLs that bypassed the Onebox allowlist and embedded malicious content in a site. This issue is fixed in versions 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
CVSS Score: 6.3

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	Low
Privileges Required	Low	Integrity Impact	Low
User Interaction	None	Availability Impact	Low

CVSS 3.1

Product Status

Vendor	discourse
Product	discourse
Versions	Version < 2026.1.7 is affected Version >= 2026.6.0-latest, < 2026.6.2 is affected Version >= 2026.7.0-latest, < 2026.7.1 is affected Version >= 2026.8.0-latest, < 2026.8.0-latest.1 is affected

References

Problem Types

CWE-20: Improper Input Validation CWE