CVE-2026-18113
CVE-2026-18113 is a Cross-site Scripting (XSS) vulnerability. O3 Security confirms whether CVE-2026-18113 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
In Concrete CMS 9.0 to 9.5.2, the Top Navigation Bar block did not HTML-escape dropdown child page names before writing them into the page, so a user who could create or rename pages…
Description
In Concrete CMS 9.0 to 9.5.2, the Top Navigation Bar block did not HTML-escape dropdown child page names before writing them into the page, so a user who could create or rename pages could store a script through a child page name and have it run in the browser of any visitor, editor, or administrator who viewed the navigation and opened the affected dropdown. In the Concrete CMS origin, the script executed with the victim's privileges and could read same-origin content or perform actions available to that user. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks labixiaoxin97 for reporting.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-18113 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-18113 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-18113. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-18113 in your dependencies?
O3 detects CVE-2026-18113 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.