CVE-2026-72722

Discourse (open‑source discussion platform) contains a vulnerability in TopicLink processing prior to versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0. The affected components are TopicLink.extract_from, TopicLink.ensure_entry_for, and TopicLink.duplicate_lookup. The root cause is that Guardia...

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...

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 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 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...

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...

PT-2026-69862

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 canonicalized slugs or titles of restricted topics...

PT-2026-69867

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 A low-privileged user can submit crafted content to the moderation review queue. Th...

PT-2026-69860

Name of the Vulnerable Software and Affected Versions Discourse versions prior to 2026.1.7 Discourse versions prior to 2026.6.2 Discourse versions prior to 2026.7.1 Discourse versions prior to 2026.8.0-latest.1 Description An HTML injection issue exists in the PrettyText.format for email function...

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-2026-69869

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-local-dates plugin renders crafted local-date format data as HTML. Th...

BIT-DISCOURSE-2026-55424 Discourse: Topic featured link susceptible to stored XSS

Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, a topic "featured link" was not sufficiently normalized and escaped before being rendered in the topic list, allowing a user who can set a featured link to inject JavaScript when default Content...

BIT-DISCOURSE-2026-53961 Discourse: Forged AWS SNS bounce notifications can disable a targeted user's email (missing TopicArn binding)

Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, the AWS SES bounce webhook at POST /webhooks/aws verified that SNS messages were signed by Amazon but did not bind them to trusted TopicArn values, allowing any AWS account holder to publish...

BIT-DISCOURSE-2026-49256 Discourse: Hidden tag names leaked via category serializers

Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, restricted tag and tag-group names attached to publicly readable categories as allowedtags, allowedtaggroups, or required tag groups could leak to anonymous and unauthorized users through categor...

BIT-DISCOURSE-2026-46413 Discourse: Regular users can route multipart uploads into the admin backup store

Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, regular users could route direct S3 multipart uploads through ExternalUploadManager into the admin backup store. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5...

BIT-DISCOURSE-2026-45788 Discourse: Secure uploads exposed by hotlinked image copying

Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, secure uploads could be exposed by pullhotlinkedimages when an attacker knew the secured upload URL and the secureuploads site setting was enabled. This issue is fixed in versions 2026.6.0,...

BIT-DISCOURSE-2026-45780 Discourse: Private event sample invitees are serialized to non-invited event viewers

Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, EventSerializer could expose invited group names, sample invitees, and attendance statistics to users who could view the topic but were not entitled to view the private event invitee list. This...

BIT-DISCOURSE-2026-44787 Discourse: Signup-time primary_group_id assignment grants whisperer access

Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, the signup flow could allow newly registered users to set primarygroupid and gain whisper-group privileges without legitimate group membership on sites with whispersallowedgroups configured. This...