EUVD-2026-86302

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the video placeholder component allowed crafted HTML to cause an attribute breakout and inject an attacker-controlled event handler. An authenticated user with default trust-level posting...

CVE-2026-91122 Discourse: Chat MessageBus delivers read-restricted messages to unauthorized users

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the video placeholder component allowed crafted HTML to cause an attribute breakout and inject an attacker-controlled event handler. An authenticated user with default trust-level posting...

CVE-2026-91122 Discourse: Chat MessageBus delivers read-restricted messages to unauthorized users

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the video placeholder component allowed crafted HTML to cause an attribute breakout and inject an attacker-controlled event handler. An authenticated user with default trust-level posting...

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...

CVE-2026-91123 Discourse: Reject literal backslash path separators in iframe src traversal guard

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...

CVE-2026-91123 Discourse: Reject literal backslash path separators in iframe src traversal guard

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...

CVE-2026-91123 Discourse: Reject literal backslash path separators in iframe src traversal guard

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...

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...

CVE-2026-91133 Discourse: Escape LIKE metacharacters in upload paths to prevent disclosure

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, authenticated users could supply unescaped SQL LIKE metacharacters to upload-resolution patterns, causing wildcard input to select unrelated upload records instead of matching a literal identifie...

CVE-2026-91133 Discourse: Escape LIKE metacharacters in upload paths to prevent disclosure

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, authenticated users could supply unescaped SQL LIKE metacharacters to upload-resolution patterns, causing wildcard input to select unrelated upload records instead of matching a literal identifie...

CVE-2026-91133

The open-source discussion platform Discourse is vulnerable to an information disclosure flaw in versions prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0 . Authenticated users can provide unescaped SQL LIKE metacharacters in upload-resolution patterns. This allows wildcard input to select unr...

EUVD-2026-86299

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, authenticated users could supply unescaped SQL LIKE metacharacters to upload-resolution patterns, causing wildcard input to select unrelated upload records instead of matching a literal identifie...

CVE-2026-91133 Discourse: Escape LIKE metacharacters in upload paths to prevent disclosure

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, authenticated users could supply unescaped SQL LIKE metacharacters to upload-resolution patterns, causing wildcard input to select unrelated upload records instead of matching a literal identifie...

CVE-2026-91134 Discourse: Block post iframes whose encoded userinfo bypasses the allowed_iframes allowlist

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the Discourse post sanitizer allowed a stored cross-origin iframe to bypass the allowediframes prefix policy when the iframe src contained encoded userinfo. The sanitizer validated a decoded form...

CVE-2026-91134 Discourse: Block post iframes whose encoded userinfo bypasses the allowed_iframes allowlist

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the Discourse post sanitizer allowed a stored cross-origin iframe to bypass the allowediframes prefix policy when the iframe src contained encoded userinfo. The sanitizer validated a decoded form...

CVE-2026-91134

The open-source discussion platform Discourse contains a vulnerability in its post sanitizer prior to versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0 . The root cause is a logic flaw where the sanitizer validates a decoded form of an iframe src differently than how the browser interprets it. ...

EUVD-2026-86298

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the Discourse post sanitizer allowed a stored cross-origin iframe to bypass the allowediframes prefix policy when the iframe src contained encoded userinfo. The sanitizer validated a decoded form...

CVE-2026-91134 Discourse: Block post iframes whose encoded userinfo bypasses the allowed_iframes allowlist

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the Discourse post sanitizer allowed a stored cross-origin iframe to bypass the allowediframes prefix policy when the iframe src contained encoded userinfo. The sanitizer validated a decoded form...

CVE-2026-84302

The open-source discussion platform Discourse is vulnerable in versions prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0 . The root cause is that reviewable visibility filtering fails to restrict Discourse AI reviewables associated with private messages. This allows moderators who are not part...

CVE-2026-84302 Discourse: Non-participant moderators can read, edit, and delete PM content through Discourse AI reviewables

Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, Discourse AI reviewables associated with private messages could appear in the moderator review queue of a moderator who was not a participant in the message. Reviewable visibility filtering did n...