Improper access control in Discourse - #VU140659
Published: August 1, 2026
Vulnerability identifier: #VU140659
CSH Severity: Low
CVSS v4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to embed malicious content in a site.
The vulnerability exists due to improper access control in the Onebox allowlist when processing specially-formed URLs. A remote user can supply a specially crafted URL to embed malicious content in a site.
Affected software
Discourse
Remediation
Install security update from vendor's website.
Discourse - addressed in versions 2026.1.7, 2026.6.2, 2026.7.1