CVE-2026-81917— Concrete CMS below 9.5.3 is vulnerable to Stored XSS in the Document Library block file description and tags
Quick assessment
Affected
Concrete CMS Concrete CMS
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.
以下是该漏洞描述的中文翻译： Concrete CMS 9.5.3 之前的版本在渲染“文档库”（Document Library）区块时，未对文件描述（description）和标签（tags）字段应用 HTML 输出转义。因此，拥有编辑文件属性权限的用户可以存储一段脚本载荷，该载荷将在浏览启用描述或标签列的页面的任何访问者（包括未认证访问者）的浏览器中执行。成功利用此漏洞可能导致会话数据被窃取，或攻击者以访问者的身份执行操作。 具体技术细节：该区块的控制器返回描述和标签的值时，未应用此前已应用于“标题”列的 转义
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I. Basic Information for CVE-2026-81917
Vulnerability Information
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Vulnerability Title
Concrete CMS below 9.5.3 is vulnerable to Stored XSS in the Document Library block file description and tags
Source: CVE Program / CVE List V5
Vulnerability Description
Concrete CMS below 9.5.3 does not apply HTML output escaping to the file description and tags fields when rendering the Document Library block, so a user with permission to edit file properties could store a script payload that executed in the browser of any visitor to a page displaying the block with the description or tags column enabled, including unauthenticated visitors. Successful exploitation could allow theft of session data or actions performed in the visitor's context. The block controller returned the description and tags values without the h() escaping already applied to the title column, and the block view template wrote the returned value directly into the results table The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 5.1 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N. Thanks Nguyen Manh Thuan for reporting.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA: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
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Concrete CMS | Concrete CMS | 5.0.0 ~ 9.5.2 | - |
|
II. Public POCs for CVE-2026-81917
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|---|
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Vendor Pages for CVE-2026-81917 (1)
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🔗 Page Not Found :: Concrete CMS release-notes
Same Patch Batch · Concrete CMS · 2026-09-11 · 15 CVEs total
| CVE-2026-81907 | 6.1 MEDIUM | Concrete CMS 9.5.2 and below is vulnerable to Cross-Site Request Forgery (CSRF) vin Expres |
| CVE-2026-81908 | 6.0 MEDIUM | Missing Authorization in Concrete CMS 9.2.0 to 9.5.2 REST API Groups List Endpoint Allows |
| CVE-2026-18122 | 6.0 MEDIUM | Concrete CMS 9.2.0 to 9.5.2 Express REST API list endpoint exposes restricted Express entr |
| CVE-2026-68528 | 6.0 MEDIUM | Concrete CMS 9.5.2 and below is vulnerable to Stored XSS in RSS Displayer Block via Unesca |
| CVE-2026-81909 | 5.9 MEDIUM | Concrete CMS 9 through 9.5.2 is vulnerable to Missing Authorization in the orphaned-block |
| CVE-2026-81910 | 5.9 MEDIUM | Concrete CMS 9 through 9.5.2 is vulnerable to Server-Side Template Injection (SSTI) in The |
| CVE-2026-81911 | 5.8 MEDIUM | Concrete CMS versions 9.0.0 to 9.5.2 is vulnerable to Stored XSS in Board Custom Slot save |
| CVE-2026-81912 | 5.7 MEDIUM | Concrete CMS before 9.5.3 is vulnerable to Cross-Site Request Forgery in the Move Multiple |
| CVE-2026-81913 | 5.3 MEDIUM | Concrete CMS versions 9.5.0 through 9.5.2 are vulnerable to Open Redirect via the rcURL pa |
| CVE-2026-68526 | 5.3 MEDIUM | Concrete CMS before 9.5.3 is vulnerable to CSRF in the Calendar event duplicate dialog con |
| CVE-2026-81915 | 5.1 MEDIUM | In Concrete CMS below 9.5.3, Page Type update omits object-level authorization |
| CVE-2026-81916 | 5.1 MEDIUM | Incorrect Authorization in the Concrete CMS Express Entries Dashboard below version 9.5.3 |
| CVE-2026-68535 | 5.1 MEDIUM | Concrete CMS 9.2.0 to 9.5.2 is vulnerable to Missing authorization in the Concrete CMS Are |
| CVE-2026-81918 | 4.8 MEDIUM | Concrete CMS below 9.5.3 is vulnerable to Stored XSS via the Date Format field in the Page |
IV. Related Vulnerabilities
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CVE-2026-81907
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Concrete CMS below 9.5.3 is vulnerable to Stored XSS via the -
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In Concrete CMS below 9.5.3, Page Type update omits object-
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In Concrete CMS below 9.5.3, Page Type update omits object-
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