CVE-2026-91123

The open-source discussion platform Discourse is vulnerable to an iframe src traversal issue in versions prior to 2026.1.8 , 2026.6.3 , 2026.7.2 , and 2026.8.0 . The root cause is that the iframe src traversal guard fails to treat literal backslashes as path separators following decoded dot segme...

EUVD-2026-86300

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the iframe src traversal guard did not treat literal backslashes as path separators after decoded dot segments. A crafted source could therefore pass an allowediframes subpath check while browser...