Improper Handling of Case Sensitivity in Discourse - #VU140007
Published: July 29, 2026
Vulnerability identifier: #VU140007
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: N/A
CWE-ID: CWE-178
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Affected software:
Discourse
Discourse
Detailed vulnerability description
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to improper input validation in the Onebox domain blocklist comparison logic when processing redirect targets. A remote attacker can use case variations in a hostname to bypass domain restrictions and disclose sensitive information.
Remediation
Install security update from vendor's website.