Discourse has 24 CVEs on record. Disclosure cadence is accelerating: 16 in the last 90 days against 0 in the 90 before. The busiest recent month was September 2026 with 10. The median CVSS is 5.4 (medium). None have a confirmed exploitation report. The dominant weakness classes are CWE-79 (10) and CWE-200 (5). Most affected products: Discourse (22), discourse-activity-pub (1), discourse-doc-categories (1).
CVEs per month
Last 12 months, by publish date
- Exploited share
- 0% vs 1% corpus
- Median CVSS
- 5.4
- Publish → KEV
- —
- Last 90 days
- 16 prev 0
Products
- Discourse 22
- discourse-activity-pub 1
- discourse-doc-categories 1
Worst active — by depth score
CVE-2026-91159High· 7.7Discourse is an open-source discussion platform54CVE-2026-91122High· 8.7Discourse is an open-source discussion platform48CVE-2026-55103High· 8.6Discourse ActivityPub adds ActivityPub support to Discourse47CVE-2026-91157High· 7.5Discourse is an open-source discussion platform41CVE-2026-91156High· 7.5Discourse is an open-source discussion platform41
Discourse vulnerabilities
CVEs affecting Discourse, newest first. Open any entry for full detail, references, and exploit status.
24 CVEsRSS
CVE-2017-20290Medium· 6.1Discourse < 1.9.0.beta13 Reflected XSS via /email/unsubscribed
Discourse 1.9.0.beta2 before 1.9.0.beta13 contains a reflected cross-site scripting vulnerability that allows unauthenticated attackers to inject scripts through the email parameter of /email/unsubscribed. Attackers can craft GET request…
CVE-2026-57447Medium· 4.3Discourse Doc Categories: Doc category index refresh leaks private topic titles
Discourse Doc Categories is a plugin for organizing Discourse topics as documentation. Prior to the verified source fix, the doc category index refresh resolves linked titles for private messages or restricted category topics without enf…
CVE-2026-55103High· 8.6Discourse ActivityPub adds ActivityPub support to Discourse
Discourse ActivityPub adds ActivityPub support to Discourse. Prior to commit 1c8518b0f2abdf31cbea3e0b242f74d8994a9ba5, inbound ActivityPub processing does not sufficiently verify that the actor authenticated by the signed request matches…
CVE-2026-91159High· 7.7PoCDiscourse is an open-source discussion platform
Discourse is an open-source discussion platform. Prior to 2026.9.0, 2026.8.1, 2026.7.3, and 2026.1.9, oEmbed processing treated an entire attacker-controlled HTML fragment as trusted when the fragment contained an iframe whose source mat…
CVE-2026-91157High· 7.5Discourse is an open-source discussion platform
Discourse is an open-source discussion platform. Prior to 2026.9.0, 2026.8.1, 2026.7.3, and 2026.1.9, sites with secure uploads enabled did not reconcile existing upload security metadata when a previously public category became read-res…
CVE-2026-91156High· 7.5Discourse is an open-source discussion platform
Discourse is an open-source discussion platform. Prior to 2026.9.0, 2026.8.1, 2026.7.3, and 2026.1.9, MessageBus audience calculation could deliver messages from a read-restricted category chat channel to an authenticated user who could …
CVE-2026-91119Medium· 6.4Discourse is an open-source discussion platform
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 action_code_who value into mention-link href attri…
CVE-2026-91120Medium· 5.4Discourse is an open-source discussion platform
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 su…
CVE-2026-91121Medium· 5.0Discourse is an open-source discussion platform
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 se…
CVE-2026-91134Medium· 5.4Discourse is an open-source discussion platform
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 allowed_iframes prefix policy when the iframe src conta…
CVE-2026-91133Medium· 6.5Discourse is an open-source discussion platform
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 unre…
CVE-2026-91132Medium· 4.3Discourse is an open-source discussion platform
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 allowed_iframes setting could accept a crafted iframe URL whose allowlisted suffix appeared after …
CVE-2026-91123High· 7.2Discourse is an open-source discussion platform
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 …
CVE-2026-91122High· 8.7Discourse is an open-source discussion platform
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…
CVE-2026-84302Medium· 4.2Discourse is an open-source discussion platform
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 parti…
CVE-2026-59830Medium· 5.4Discourse is an open-source discussion platform
Discourse is an open-source discussion platform. Prior to 2026.7.0, the post action component failed to escape user-controlled display names before interpolating them into an HTML string passed to trustHTML. A user who could choose a cra…
CVE-2026-27481Medium· 5.3Discourse is an open-source discussion platform
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 authorization bypass vulnerability allows unauthenticated o…
CVE-2026-32618Medium· 4.3Discourse is an open-source discussion platform
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, there is possible channel membership inference from chat user …
CVE-2026-32615Medium· 5.4Discourse is an open-source discussion platform
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, category group moderators could perform privileged actions on …
CVE-2026-32607Medium· 5.4Discourse is an open-source discussion platform
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, when the hidden prioritize_full_name_in_ux site setting is ena…
CVE-2026-32273Medium· 5.4Discourse is an open-source discussion platform
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, updating a category description via API is not sanitizing the …
CVE-2026-32243Medium· 5.4Discourse is an open-source discussion platform
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…
CVE-2026-32143Medium· 6.5Discourse is an open-source discussion platform
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, moderators could export CSV data for admin-restricted reports,…
CVE-2026-32113Medium· 6.1Discourse is an open-source discussion platform
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, the enter action in StaticController reads the sso_destination…