BIT-DISCOURSE-2026-72728 Discourse: Onebox iframe origin allowlist enforces URL authority boundary

Discourse is an open-source discussion platform. Prior to 2026.1.7, an authenticated user could submit specially formed URLs that bypassed the Onebox allowlist and embedded malicious content in a site. This issue is fixed in versions 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0...

BIT-DISCOURSE-2026-72724 Discourse: Private Chat Threat Message Disclosure via Chat Onebox Channel/Threat ID Mismatch

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...

BIT-DISCOURSE-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-2026-72724

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...

EUVD-2026-55667

Discourse is an open-source discussion platform. Prior to 2026.1.7, an authenticated user could submit specially formed URLs that bypassed the Onebox allowlist and embedded malicious content in a site. This issue is fixed in versions 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1...

CVE-2026-72728 Discourse: Onebox iframe origin allowlist enforces URL authority boundary

Discourse is an open-source discussion platform. Prior to 2026.1.7, an authenticated user could submit specially formed URLs that bypassed the Onebox allowlist and embedded malicious content in a site. This issue is fixed in versions 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1...

CVE-2026-72728

Discourse pre-2026.1.7 is affected by a Onebox iframe origin allowlist bypass. An authenticated user could submit specially formed URLs that bypassed the allowlist and embedded malicious content in a site. Affected component is the Onebox URL handling; root cause is improper enforcement of the UR...

CVE-2026-72724

Discourse vulnerability CVE-2026-72724 affects the chat onebox flow. Prior to versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, plugins/chat/lib/chat/onebox_handler.rb resolves Chat::Thread by route thread_id independently of the route channel_id before verifying preview permissions, allowing ...

CVE-2026-72724 Discourse: Private Chat Threat Message Disclosure via Chat Onebox Channel/Threat ID Mismatch

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...

EUVD-2026-55657

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...

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...

Discourse Information Disclosure Vulnerability (CNVD-2026-17249)

Discourse is Discourse open source set of open source community discussion platform. The platform includes features such as community , e-mail and chat rooms . An information disclosure vulnerability exists in Discourse. The vulnerability stems from the fact that an authenticated user can send an...

BIT-DISCOURSE-2026-32951 Discourse: Authorization bypass in oneboxer via user-controlled category id

Discourse is an open-source discussion platform. From versions 2026.1.0 to before 2026.1.3, and 2026.2.0 to before 2026.2.2, an authenticated user can obtain shared draft topic titles by sending an inline onebox request with a categoryid parameter matching the shared drafts category. This issue h...

BIT-DISCOURSE-2026-32243 Discourse: Stored XSS in discourse-ai shared conversations onebox

Discourse is an open-source discussion platform. From versions 2026.1.0 to before 2026.1.3, and 2026.2.0 to before 2026.2.2, an attacker with the ability to create shared AI conversations could inject arbitrary HTML and JavaScript via crafted conversation titles. This payload would execute in the...

CVE-2026-32243

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, an attacker with the ability to create shared AI conversations could inject arbitrary HTML and JavaScript via crafted...

CVE-2026-32951

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, an authenticated user can obtain shared draft topic titles by sending an inline onebox request with a categoryid parameter...

CVE-2026-32951

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, an authenticated user can obtain shared draft topic titles by sending an inline onebox request with a categoryid parameter...

CVE-2026-32243

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, an attacker with the ability to create shared AI conversations could inject arbitrary HTML and JavaScript via crafted...