CVE-2026-72721 Discourse: Onebox Domain Blocklist Bypass via Case-Sensitive Comparison

Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, Onebox::DomainChecker.isblocked? compares hostnames and SiteSetting.blockedoneboxdomains entries case-sensitively, allowing an attacker to bypass configured Onebox domain restrictions by changing...

CVE-2026-72721

Findings: CVE-2026-72721 affects Discourse prior to versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0. The root cause is a case-sensitive comparison in Onebox::DomainChecker.is_blocked?, which compares hostnames and SiteSetting.blocked_onebox_domains entries. This allows an attacker to bypass c...

CVE-2026-72721 Discourse: Onebox Domain Blocklist Bypass via Case-Sensitive Comparison

Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, Onebox::DomainChecker.isblocked? compares hostnames and SiteSetting.blockedoneboxdomains entries case-sensitively, allowing an attacker to bypass configured Onebox domain restrictions by changing...

CVE-2026-72720 Discourse: HTML injection in PrettyText.format_for_email from cooked-attribute reparsing

Discourse is an open-source discussion platform. Prior to 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1, Discourse has HTML injection in PrettyText.formatforemail because cooked attribute values are reparsed as markup. Crafted Vimeo iframe sources, secure-upload URLs or dimensions, and...

CVE-2026-72720 Discourse: HTML injection in PrettyText.format_for_email from cooked-attribute reparsing

Discourse is an open-source discussion platform. Prior to 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1, Discourse has HTML injection in PrettyText.formatforemail because cooked attribute values are reparsed as markup. Crafted Vimeo iframe sources, secure-upload URLs or dimensions, and...

EUVD-2026-55656

Discourse is an open-source discussion platform. Prior to 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1, Discourse has HTML injection in PrettyText.formatforemail because cooked attribute values are reparsed as markup. Crafted Vimeo iframe sources, secure-upload URLs or dimensions, and...

CVE-2026-72720

Discourse is an open-source discussion platform. Prior to 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1, Discourse has HTML injection in PrettyText.formatforemail because cooked attribute values are reparsed as markup. Crafted Vimeo iframe sources, secure-upload URLs or dimensions, and...

CVE-2026-72720 Discourse: HTML injection in PrettyText.format_for_email from cooked-attribute reparsing

Discourse is an open-source discussion platform. Prior to 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1, Discourse has HTML injection in PrettyText.formatforemail because cooked attribute values are reparsed as markup. Crafted Vimeo iframe sources, secure-upload URLs or dimensions, and...

CVE-2026-72720

CVE-2026-72720 affects the Discourse open‑source forum platform. The issue is an HTML injection vulnerability in PrettyText.format_for_email where cooked attribute values are reparsed as markup, enabling decoded attribute text from crafted Vimeo iframe sources, secure-upload URLs or dimensions, a...

PT-2026-69864

Name of the Vulnerable Software and Affected Versions Discourse versions prior to 2026.1.6 Discourse versions prior to 2026.5.2 Discourse versions prior to 2026.6.1 Discourse versions prior to 2026.7.0 Description An authenticated user can obtain private thread message content by pairing a public...

PT-2026-69865

Name of the Vulnerable Software and Affected Versions Discourse versions prior to 2026.1.6 Description The staff action log model renders unescaped previous and new value fields, allowing the injection of stored cross-site scripting XSS into the staff interface. Stored XSS is a type of...

CVE-2026-72725: Improper Neutralization of Input During Web Page Generation

Discourse is an open-source discussion platform. Prior to 2026.1.6, the staff action log model rendered unescaped previous and new value fields that could inject stored cross-site scripting into the staff interface. The issue is fixed in 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0...

CVE-2026-72727: Improper Neutralization of Input During Web Page Generation

Discourse is an open-source discussion platform. Prior to 026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, a low-privileged user could place crafted content in the moderation review queue that executed stored cross-site scripting when a moderator viewed it on a site with a modified or disabled default...

CVE-2026-72722: Missing Authorization

Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, TopicLink.extractfrom, TopicLink.ensureentryfor, and TopicLink.duplicatelookup do not consistently enforce Guardian.cansee? checks when processing internal links. An authenticated user can submit...

CVE-2026-72724: Authorization Bypass Through User-Controlled Key

Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, plugins/chat/lib/chat/oneboxhandler.rb resolves Chat::Thread by route threadid independently of the route channelid before checking whether the user can preview the selected chat channel. An...

CVE-2026-72731: Improper Neutralization of Special Elements used in an SQL Command

Discourse is an open-source discussion platform. From 2026.1.0-latest until 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1, anyone able to run a parameterized Data Explorer query, including non-staff members of a group a query is shared with, could craft parameter values that escaped the...

PT-2026-69877

Name of the Vulnerable Software and Affected Versions Discourse versions prior to 2026.1.6 Discourse versions prior to 2026.5.2 Discourse versions prior to 2026.6.1 Discourse versions prior to 2026.7.0 Description The discourse templates endpoint exposes hidden tag names because the...

CVE-2026-72720: Improper Neutralization of Input During Web Page Generation

Discourse is an open-source discussion platform. Prior to 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1, Discourse has HTML injection in PrettyText.formatforemail because cooked attribute values are reparsed as markup. Crafted Vimeo iframe sources, secure-upload URLs or dimensions, and...

CVE-2026-72730: Improper Neutralization of Input During Web Page Generation

Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, the Rich Text Editor rendered a chat-transcript username as HTML, allowing stored cross-site scripting. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0...

CVE-2026-72729: Improper Neutralization of Input During Web Page Generation

Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, the discourse-local-dates plugin rendered crafted local-date format data as HTML on sites with a modified or disabled default Content Security Policy. This issue is fixed in versions 2026.1.6,...