CVE-2026-91119 Discourse: Encode action_code_who in mention URLs

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the topic small-action and nested-activity-log components interpolated the free-form actioncodewho value into mention-link href attributes without URL encoding. A quote-bearing display name could...

CVE-2026-91119

The open-source discussion platform Discourse is vulnerable to stored HTML injection in versions prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0. The small-action and nested-activity-log components fail to perform URL encoding when interpolating the free-form action_code_who value into mentio...

EUVD-2026-86307

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the topic small-action and nested-activity-log components interpolated the free-form actioncodewho value into mention-link href attributes without URL encoding. A quote-bearing display name could...

CVE-2026-91121 Discourse: Chat upload filenames rendered as raw HTML in excerpts

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, attacker-controlled upload filenames used in chat message excerpts were rendered as unescaped HTML. A user able to upload a file and send chat content could place markup in a filename that was th...

CVE-2026-91121 Discourse: Chat upload filenames rendered as raw HTML in excerpts

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, attacker-controlled upload filenames used in chat message excerpts were rendered as unescaped HTML. A user able to upload a file and send chat content could place markup in a filename that was th...

CVE-2026-91121

The Discourse open-source discussion platform is vulnerable to trusted-HTML injection in versions prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0 . The root cause is that attacker-controlled upload filenames used in chat message excerpts are rendered as unescaped HTML . An attacker capable of...

EUVD-2026-86306

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, attacker-controlled upload filenames used in chat message excerpts were rendered as unescaped HTML. A user able to upload a file and send chat content could place markup in a filename that was th...

CVE-2026-91121 Discourse: Chat upload filenames rendered as raw HTML in excerpts

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, attacker-controlled upload filenames used in chat message excerpts were rendered as unescaped HTML. A user able to upload a file and send chat content could place markup in a filename that was th...

EUVD-2026-86304

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, provider-controlled video titles in lazy video embeds could be reparsed as HTML when Discourse generated notification emails or chat summaries. A user with standard posting privileges could creat...

CVE-2026-91120 Discourse: Stored HTML injection in video notification emails

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, provider-controlled video titles in lazy video embeds could be reparsed as HTML when Discourse generated notification emails or chat summaries. A user with standard posting privileges could creat...

CVE-2026-91120 Discourse: Stored HTML injection in video notification emails

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, provider-controlled video titles in lazy video embeds could be reparsed as HTML when Discourse generated notification emails or chat summaries. A user with standard posting privileges could creat...

CVE-2026-91120

The open-source discussion platform Discourse contains a stored HTML injection vulnerability in its video notification email and chat summary generation. Prior to versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0 , provider-controlled video titles from lazy video embeds (YouTube, Vimeo, or TikT...

CVE-2026-91120 Discourse: Stored HTML injection in video notification emails

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, provider-controlled video titles in lazy video embeds could be reparsed as HTML when Discourse generated notification emails or chat summaries. A user with standard posting privileges could creat...

CVE-2026-91132 Discourse: Wildcard iframe origin allowlist bypass via authority separators

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, sites using wildcard patterns in the allowediframes setting could accept a crafted iframe URL whose allowlisted suffix appeared after a URL authority separator. The wildcard origin check matched...

CVE-2026-91132 Discourse: Wildcard iframe origin allowlist bypass via authority separators

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, sites using wildcard patterns in the allowediframes setting could accept a crafted iframe URL whose allowlisted suffix appeared after a URL authority separator. The wildcard origin check matched...

CVE-2026-91132

The open-source discussion platform Discourse contains a vulnerability in versions prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0 . Sites utilizing wildcard patterns in the allowed_iframes setting are susceptible to a bypass where a crafted iframe URL places an allowlisted suffix after a URL...

CVE-2026-91132 Discourse: Wildcard iframe origin allowlist bypass via authority separators

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, sites using wildcard patterns in the allowediframes setting could accept a crafted iframe URL whose allowlisted suffix appeared after a URL authority separator. The wildcard origin check matched...

EUVD-2026-86303

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, sites using wildcard patterns in the allowediframes setting could accept a crafted iframe URL whose allowlisted suffix appeared after a URL authority separator. The wildcard origin check matched...

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...