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CVE-2026-33395— Discourse has stored click‑based XSS via Graphviz SVG javascript: links

CVSS 4.4 · Medium EPSS 0.02% · P5
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I. Basic Information for CVE-2026-33395

Vulnerability Information
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Vulnerability Title
Discourse has stored click‑based XSS via Graphviz SVG javascript: links
Source: NVD (National Vulnerability Database)
Vulnerability Description
Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the discourse-graphviz plugin contains a stored cross-site scripting (XSS) vulnerability that allows authenticated users to inject malicious JavaScript code through DOT graph definitions. For instances with CSP disabled only. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, disable the graphviz plugin, upgrade to a patched version, or enable a content security policy.
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N
Source: NVD (National Vulnerability Database)
Vulnerability Type
在Web页面生成时对输入的转义处理不恰当(跨站脚本)
Source: NVD (National Vulnerability Database)
Vulnerability Title
Discourse 跨站脚本漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Discourse是Discourse开源的一套开源的社区讨论平台。该平台包括社区、电子邮件和聊天室等功能。 Discourse 2026.3.0-latest.1之前版本、2026.2.1之前版本和2026.1.2之前版本存在跨站脚本漏洞，该漏洞源于discourse-graphviz插件中存在存储型跨站脚本，可能导致经过身份验证的用户通过DOT图定义注入恶意JavaScript代码。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

VendorProductAffected VersionsCPESubscribe
discoursediscourse >= 2026.1.0-latest, < 2026.1.2 -

II. Public POCs for CVE-2026-33395

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III. Intelligence Information for CVE-2026-33395

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Advisory · 1Patch · 3

Same Patch Batch · discourse · 2026-03-19 · 17 CVEs total

CVE-2026-333556.5 MEDIUMDiscourse filters whisper posts from private-posts feed
CVE-2026-334105.4 MEDIUMDiscourse hardens chat DM channel creation and expansion
CVE-2026-274545.3 MEDIUMDiscourse has check revision visibility on posts endpoint
CVE-2026-320994.3 MEDIUMDiscourse prevents hidden profile data leak via user onebox
CVE-2026-333934.3 MEDIUMDiscourse fixes loose hostname matching in spam host allowlist
CVE-2026-271664.1 MEDIUMDiscourse vulnerable to HTML injection via prohibited iframe URLs
CVE-2026-333942.7 LOWDiscourse leaks PM post edits to moderators
CVE-2026-334082.2 LOWDiscourse has Improper Authorization in "Post Edits" Report For Moderators
CVE-2026-27491Discourse has a bypass of official warnings messages by non-staff users
CVE-2026-27570Discourse Vulnerable to Stored XSS via Shared AI Conversation Onebox
CVE-2026-27740Discourse has Stored XSS in AI Triage Automation
CVE-2026-27934Discourse leaks private topic title and post excerpt via user action API endpoint
CVE-2026-27935Discourse leaks private topic metadata to non-authorized users
CVE-2026-27936Discourse discloses restricted post-action counts to non-privileged users
CVE-2026-28282Discourse vulnerable to group membership addition permission bypass via discourse-policy p
CVE-2026-29072Discourse missing permission check for policy creation in discourse-policy

IV. Related Vulnerabilities

Same product: discourse
Same vendor: discourse
Same weakness: CWE-79

V. Comments for CVE-2026-33395

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