Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1336 CNY

100%
Buy Us a Coffee

CVE-2026-18116— Concrete CMS 8.3.0 to 9.5.2 is vulnerable to Stored XSS in Calendar Event Name via Workflow Approval Notifications

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.

Concrete CMS 8.3.0 至 9.5.2 版本中，日历事件名称在存储时未进行净化处理，且在仪表盘的“待我处理”（Waiting For Me）区块中展示工作流审批和删除通知时，未对事件名称进行 HTML 转义。 任何被授权向受审批工作流管控的日历添加事件的注册用户，都可以提交一个事件名称中包含脚本载荷的事件。当该待处理请求在管理员的浏览器中显示时，该脚本会被执行，攻击者可借此创建一个新的管理员账户。 Concrete CMS 安全团队为此漏洞赋予的 CVSS v4.0 评分为 7.3，向量值为： CVS

CVSS 7.3 · High

Possible ATT&CK Techniques 2 AI

T1189 · Drive-by Compromise T1189.002
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-18116

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
Concrete CMS 8.3.0 to 9.5.2 is vulnerable to Stored XSS in Calendar Event Name via Workflow Approval Notifications
Source: CVE Program / CVE List V5
Vulnerability Description
Concrete CMS 8.3.0 to 9.5.2 stored calendar event names without sanitization and rendered them without HTML escaping in the workflow approval and deletion notifications shown in the dashboard "Waiting For Me" block. A registered user permitted to add events to a calendar governed by an approval workflow could submit an event whose name contained a script payload, which then executed in an administrator's browser when the pending request was displayed and could be used to create a new administrator account. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks v01demort for reporting.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/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 8.3.0 ~ 9.5.2 -

II. Public POCs for CVE-2026-18116

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-18116

请登录查看更多情报信息。

Vendor Pages for CVE-2026-18116 (1)

Same Patch Batch · Concrete CMS · 2026-09-14 · 7 CVEs total

CVE-2026-18117 7.3 HIGH Concrete CMS 9.0.0 to 9.5.2 is vulnerable to Stored XSS in Custom Page Alias Name
CVE-2026-81900 7.3 HIGH Concrete CMS before 9.5.3 is vulnerable to Stored XSS in the YouTube block (vWidth/vHeight
CVE-2026-81901 7.2 HIGH Concrete CMS 9.2.0 to 9.5.2 is vulnerable to stored XSS due to missing authorization in th
CVE-2026-81902 7.1 HIGH Concrete CMS 9.0.0 to 9.5.2 is vulnerable to CSRF on Orphan Block Cleanup
CVE-2026-18119 7.0 HIGH Concrete CMS below 9.5.3 is vulnerable to Stored XSS via unsanitized inline block custom s
CVE-2026-81903 7.0 HIGH Concrete CMS 9.0.0 to 9.5.2 is vulnerable to Stored XSS via Page Container icon

IV. Related Vulnerabilities

Same product: Concrete CMS
Same vendor: Concrete CMS
Same weakness: CWE-79

V. Comments for CVE-2026-18116

No comments yet

Leave a comment