CVE-2026-33411— Discourse's solved topic stream has potential stored XSS in topic title
Quick assessment
Affected
discourse discourse
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
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，该漏洞源于已解决帖子流中的主题标题处理不当，可能导致存储型跨站脚本攻击。
Possible ATT&CK Techniques 1 AI
T1059 · Command and Scripting Interpreter
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I. Basic Information for CVE-2026-33411
Vulnerability Information
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Vulnerability Title
Discourse's solved topic stream has potential stored XSS in topic title
Source: CVE Program / CVE List V5
Vulnerability Description
Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 have a potential stored XSS in topic titles for the solved posts stream. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, ensure that the Content Security Policy is enabled, and has not been modified in a way which would make it more vulnerable to XSS attacks.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Source: CVE Program / CVE List V5
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: CVE Program / CVE List V5
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，该漏洞源于已解决帖子流中的主题标题处理不当，可能导致存储型跨站脚本攻击。
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
II. Public POCs for CVE-2026-33411
| # | POC Description | Source Link | Shenlong Link |
|---|
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Vendor Advisories for CVE-2026-33411 (1)
Same Patch Batch · discourse · 2026-03-20 · 16 CVEs total
| CVE-2026-33424 | 5.9 MEDIUM | PM access granted through invites after access revocation |
| CVE-2026-33251 | 5.4 MEDIUM | Discourse has a Hidden Solved topics permission bypass |
| CVE-2026-31805 | 5.3 MEDIUM | Discourse has a poll authorization bypass via post_id array parameter |
| CVE-2026-33422 | 3.5 LOW | Discourse exposes ip_address of flagged user |
| CVE-2026-33426 | 3.5 LOW | Discourse users can edit or synonymize hidden tags they can't see |
| CVE-2026-30888 | 2.2 LOW | Discourse has moderator privilege escalation via arbitrary post_id in suspend/silence endp |
| CVE-2026-31869 | Discourse: Composer mentions endpoint leaks hidden group membership through PM `allowed_na | |
| CVE-2026-30889 | Discourse has Unauthorized Post Data Exposure in discourse-user-notes | |
| CVE-2026-30891 | Discourse hasUnauthorized Exposure of Private User Action Types | |
| CVE-2026-32114 | Discourse's unscoped status lookups leak restricted metadata | |
| CVE-2026-33291 | Discourse user can create Zendesk tickets even when it does not have access to topic | |
| CVE-2026-33423 | Discourse staff can modify any user's group notification level | |
| CVE-2026-33425 | Discourse has inferable private group membership or existence via exclude_groups parameter | |
| CVE-2026-33427 | Discourse Authorization Page Displays Unvalidated Redirect Domain | |
| CVE-2026-33428 | Discourse Allows Unauthorized Access to Deleted Posts Index via Group Membership |
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Same vendor: discourse
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CVE-2026-91119
Discourse: Encode action_code_who in mention URLs -
CVE-2026-91121
Discourse: Chat upload filenames rendered as raw HTML in exc -
CVE-2026-91120
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CVE-2026-91122
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Same weakness: CWE-79
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V. Comments for CVE-2026-33411
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